While there are isolated instances of African Americans serving in the Confederate ranks, there is overwhelming evidence that this small number represents rare and exceptional cases: historian David Blight estimates that the number of black soldiers in the Confederate ranks was fewer than 200. That small number represents some partial companies of slaves training as soldiers discovered by Union forces after the fall of Richmond. One reason that only a handful of blacks fought for the Confederacy is that until the last weeks of the war, the Confederate Congress expressly forbade arming enslaved African Americans, who made up the vast majority of the black population in the South. Given white southerners' longstanding fears of a slave uprising (fears intensified by a few abortive attempts in the first half of the 19th century and exacerbated to the point of hysteria by John Brown's raid on Harper's Ferry in 1859), the acute resistance of Confederates to arming blacks is understandable. Putting muskets in the hands of enslaved African Americans presented more than simply a concrete threat—embracing the notion that blacks could serve as soldiers in the same fashion as whites threatened deeply-held Southern ideas of race-based honor and masculinity. As Confederate Secretary of State Robert Toombs put it, "The day the army of Virginia allows a negro regiment to enter their lines as soldiers, they will be degraded, ruined, and disgraced."

Northerners were scarcely more enthusiastic about arming African Americans than their Southern counterparts. For the first year and a half of the war, Abraham Lincoln's administration eschewed the enlistment of black troops, fearful of a public backlash. Not until Lincoln signed the Emancipation Proclamation on January 1, 1863, did the Union Army begin to enroll African Americans in its ranks; even then, the decision proved deeply controversial, particularly among Northern Democrats. The Confederacy did not seriously entertain the idea of arming enslaved African Americans until a full year later, when the war situation in the South had grown much more desperate. In January 1864, months after the defeats at Gettysburg and Vicksburg, Patrick Cleburne (one of the most successful combat commanders in the Confederate Army) circulated a proposal to arm the slaves. Northern successes on the battlefield, Cleburne argued, threatened the South with "the loss of all we now hold most sacred—slaves and all other personal property, lands, homesteads, liberty, justice, safety, pride, manhood." Sacrificing the first, Cleburne held, could save the rest; the Confederacy could check Union advances by recruiting an army of slaves and guaranteeing freedom "within a reasonable time to every slave in the South who shall remain true to the Confederacy." A dozen of Cleburne's subordinates backed his proposal.

To most Southerners, however, Cleburne's plan was appalling. The prospect of arming the slaves struck one division commander as "revolting to Southern sentiment, Southern pride, and Southern honor." A brigade commander suggested that accepting enslaved African Americans as soldiers would "contravene the principles upon which we fight." Sensing the potential for the debate to cause dangerous dissension within the ranks, Confederate President Jefferson Davis ordered the generals to cease the discussion. Debate over the decision to arm enslaved African Americans resurfaced many months later, as the Confederacy's situation grew progressively more dire both on and off the battlefield. When another similar proposal reemerged it carried the imprimatur of Robert E. Lee, commander of the Army of Northern Virginia and perhaps the most revered figure in the South. In February 1865, Lee wrote a letter to a Confederate congressman characterizing the plan as "not only expedient but necessary." Even with Lee's support, though, the bill proved deeply divisive. It was not until March 13, 1865, just weeks before Lee's surrender, that the Confederate Congress passed legislation allowing for the enlistment of black soldiers. The two companies discovered by Union troops after the fall of Richmond never went into battle. Opposition to African American soldiers was passionate on both sides. The notion of fighting alongside blacks violated many deeply-held beliefs of white Northerners and Southerners alike. In the Union army, African Americans served in segregated regiments under white officers; many were used for menial tasks rather than fighting, and those that went into combat suffered abuse from their white comrades and were often singled out as targets by their Confederate foes. Nevertheless, the vast majority of African American troops fought bravely and with distinction, and by the end of the war, their actions in combat had begun to change the assumptions of at least some of their comrades regarding the fitness of blacks for battle. Despite their demonstrated fighting ability, it was nearly another full century before the United States Army finally desegregated individual units.

I’m not sure how this question defines “great civilization,” but it seems that, like most other people educated in the United States, the questioner is unaware of the highly stratified, centralized, and elaborate societies that did exist north of the Rio Grande prior to the arrival of Europeans. We are taught that Indian societies in North America had no governments, class structures, religions, intellectual traditions, or other elements of what Western European philosophy calls “civilization.” But to contrast that view, I'll offer a few examples. I think we can fairly say that all societies, regardless of how elaborate their social and political structures may be, are “civilized.” The largest city in North America prior to 1492 was called Cahokia, located on what is today the Missouri River across from St. Louis. As a city-state, the population of 15,000 people was comparable to London or Paris at that time. Cahokia was the center of an elaborate trade network that stretched across the entire continent from 950 to 1250 AD. City residents, along with laborers from far away, traveled to Cahokia over the course of several hundred years to build enormous earthen mounds. The largest one is 15 acres around and is the largest earthen structure in the Western Hemisphere. These mounds—not unlike European cathedrals in spiritual or architectural significance—served as symbols of power for elite religious and political leaders. These leaders often lived atop the mounds to be closer to the sun, their spiritual source of power. The influence these leaders possessed was enormous. Not only could they command the construction of mounds, but they held the reins of the city's economic and military fortunes as well. Because of the extent of Cahokia's trade networks, the consequences of their decisions were felt all over the continent.

Another immense center of trade and spiritual power was located in Chaco Canyon in what is now New Mexico. Inhabitants and visitors to the canyon built 12 structures between 900 and 1150 AD, which had 200 or more contiguous, multistoried rooms and numerous “kivas,” or round, windowless areas that today the Hopi and Pubelo Indians (descendants of the people who built Chaco) use for worship. Like Cahokia, the labor required to build such structures must have been enormous and well-coordinated, evincing a sophisticated political, economic, scientific, and social organization. Surrounding these 12 structures were between 200 and 350 villages in the canyon. An estimated 15,000 people inhabited the area. Among archaeologists, two theories are popular about why Chaco was built. The first centers on trade and exchange. Archaeologists have found items from Mexico and Central America in towns and villages up to 60 miles away from the central part of the canyon, along with a system of roads. This evidence leads them to speculate that the Chaco structures were the center of trade, where people bought and sold goods. The second theory involves the scientific and spiritual dimensions of the buildings. The structures are built in line with astronomical movements of the sun, moon, planets, and stars, leading some to believe that it was in fact a kind of three-dimensional calendar, a much more elaborate version of Stonehenge in England. Settlers in the canyon would have gone there to worship at certain times of the year to be reminded of the order of the universe and their place in it. Ultimately, both these scenarios could exist. Certainly by anyone’s standards, a society that so fully integrated spiritual, scientific, and material aspects of life would qualify as a “great civilization.” If, however, by comparing North and South America you mean to ask why did North America not develop the exact same kind of societies that Central and South America did, then one answer to that may be population density. Central Mexico alone had 25.2 million people in 1491, making it the most densely populated place on earth. The whole continent of North America, by contrast, had 12–20 million people. As we see throughout human history and all over the world, higher numbers of people tend to lead to more highly stratified societies.

Pershing undoubtedly had complex views on race and American citizenship, probably not so different from his political ally and fellow Republican, Theodore Roosevelt. Given his command of African American “Buffalo Soldiers” in the 1898 Spanish-American War and his participation in the Wounded Knee Massacre of Lakota Indians just eight years earlier, it would seem that he held very contradictory views. To Pershing, blacks may have seemed like worthy soldiers, while Indians deserved genocide. On the other hand, as a military officer, Pershing was carrying out orders and we cannot assume these actions reflected his personal beliefs. Roosevelt, however, was in a different position. Unlike Pershing, who followed orders, Roosevelt gave orders and thus set the tone for race relations both in the military and in society at large. For example, Roosevelt was determined to see the cultural extinction of American Indians (while holding them up as “noble savages” nonetheless), but he also hosted black educator Booker T. Washington at the White House, a very controversial move, especially to white Southern Democratic politicians.

As the first two decades of the 20th century passed, the nation saw increased immigration from both Europe and Asia, as well as increased activism by African Americans, American Indians, and others who demanded equal opportunities and the end of discriminatory laws and customs. World War I was a watershed in these movements, as both African Americans and American Indians enlisted in the army. Blacks served in segregated units, but Indians did not. Indians had a highly ambivalent attitude about their senses of belonging to the American nation; after all, they belonged to tribal nations as well, nations which had long histories of government-to-government relations with the United States. Yet by 1918, the federal government had done a good deal to not only destroy Indian lives but to destroy that government-to-government relationship as well. Many Indians were resentful of these policies, but chose to join the military anyway. Why? Veterans have offered many reasons, one of which is that they believed that when America was threatened, their homelands were threatened. Many veterans saw themselves as warriors not only for their own tribal communities but for the U.S. as well. Despite their service alongside whites, there is no doubt that Indians experienced a high degree of discrimination in the military, as sensitively shown by Joseph Boyden in the novel Three Day Road. Both Indians and blacks sacrificed for the United States and felt that the country ought to treat them more fairly. Woodrow Wilson, a Democrat who had to maintain political support from southern white supremacist Democrats, vacillated on this issue (especially in his refusal to support anti-lynching legislation in Congress) and questions of African American integration in the military were essentially abandoned until after World War II. Wilson, like so many other policy makers, seemed to effectively ignore Indian concerns. Indians’ service with whites in the military might be explained by the emerging notion of “whiteness.” Whiteness is an analytical category that historians have used to explain the shifts in race relations created by immigration and industrialization in the late 19th and early 20th centuries. We must remember that men like Roosevelt and Pershing talked about “race” in what today we would think of as ethnic or national terms—there was an English race, an Irish race, a German race, an Italian race, and so on. Today, we tend to think of these ethnicities as “white,” though that idea was hardly solidified in the early twentieth century. Instead, a long historical process created “whiteness” and a white population out of many different nationalities once perceived as incompatible and even threatening to Anglo-Saxon Americans.

Famously, Roosevelt believed in the “melting pot,” a phrase that we have come to associate with his belief in equality and the worth of all men, but which in actuality referred to his wish to see Americans with ancestry in Western Europe mix and marry one another. It was only those Americans who could jump into the melting pot—Asians, African Americans, American Indians, and others were explicitly excluded from Roosevelt’s vision of a strong American people. Yet, Indians were not segregated in military service, despite the fact that every American president had endorsed a policy that would essentially exterminate them. These policies had not wholly succeeded, but at the turn of the 20th century the American Indian population was at its lowest in human history. In this light, we can imagine that Indians were not perceived as a threat to whiteness in the same way that Southern Europeans, Eastern Europeans, Asians, and African Americans were. By the 1920s, immigrants from places seen as undesirable to Anglo-Saxon policy makers had increased so much that Congress passed the 1924 Immigration Act. This act installed quotas on immigrants from certain countries; in general, the number of immigrants from Southern and Eastern Europe and Asia could not exceed 2% of those populations currently living in the US, as of the 1890 census. In other words, if, say, 100,000 people from China lived in the United States in 1890, then the US would admit no more than 2,000 people in a given year. Pershing, who was close to President Calvin Coolidge and had even considered a run for the Republican Presidential nomination in 1920, was present for the signing of this bill, indicating his support for it and what it represented for policy-makers’ hopes about the future racial composition of the United States. Of course, we now know that this policy ultimately did not achieve its intended effect, however much “whiteness” is taken for granted today. Indeed, what this period shows is that the racial hierarchies we believe to have always been in place were in considerable flux even as recently as 100 years ago. Pershing, Roosevelt, Wilson, and Coolidge were at the forefront of maintaining white supremacy, but they could not ignore the consistent—and insistent—protest of non-white Americans, nor should we ignore the fact that within white and non-white communities, there are very distinct groups with different histories who possessed varied responses to their situations in the United States.

The United States Constitution does not state in so many words that there is a separation of church and state. The first part of the First Amendment to the Constitution states: “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.” Therefore, it is more accurate to say that the Constitution promotes freedom of religion and prohibits the federal government from inhibiting its citizens’ ability to worship as they wish.

There were some colonial predecessors to this concept. For example, when Roger Williams was banned from Massachusetts Bay for his religious beliefs in 1636, he founded the colony of Rhode Island on the premise that persons of all religions were welcome. In 1649 Lord Baltimore drafted the Maryland Toleration Act, which protected Maryland colonists’ rights to worship as they pleased, and William Penn’s colony of Pennsylvania, founded in 1681, also welcomed persons of diverse religions, although only Anglicans and Quakers could hold political office. The expression “separation of church and state” can be traced to an 1802 letter that Thomas Jefferson wrote to a group of men affiliated with the Danbury Baptists Association of Connecticut. In this letter he stated that religion was “a matter which lies solely between Man & his God,” and that government should not have any influence over opinions. Therefore, he asserted: “I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should ‘make no law respecting an establishment of religion, or prohibiting the free exercise thereof,’ thus building a wall of separation between Church & State.” Jefferson was a member of the Church of England throughout his life. However, while a student at William and Mary, Jefferson became a follower of Deism, an enlightenment-era religion based on reason and observation of the natural world that grew out of the Enlightenment. Deists rejected the idea of supernatural occurrences, such as miracles, and they believed that God created the universe, but did not interfere in its workings. Jefferson introduced the Virginia Statute of Religious Freedom in 1779, which became law in 1786. It separated Virginia government from any established church and asserted that the religious opinions of men were not the business of the government.

Lone Wolf v Hitchcock (187 U.S. 553, 1903) was part of a long string of treaties and legislative and judicial measures that displaced North America’s First Peoples from their ancestral lands, hemmed them into “reservations,” and eventually detribalized them. This Supreme Court decision originated on the Kiowa-Comanche reservation, which the Medicine Lodge Treaty (1867) had established in Indian Territory. The treaty guaranteed the Kiowa and Comanche “absolute and undisturbed use and occupation” of these reservation lands and stipulated that in order for any portion of the reservation lands to be ceded to the U.S., three-fourths of the adult males in the tribe had to give their approval. However, in 1900, without Native American consent, Congress passed an Allotment Act that divided the Kiowa-Comanche lands into 160-acre allotments to give to the Native American residents of the reservation. Those who accepted the allotments were also given American citizenship. The “surplus” lands left after the allotment were to be sold to whites, and the Kiowa and Comanche were to receive about one dollar per acre for these lands. In 1902, Kiowa headman Lone Wolf sued newly-appointed Secretary of the Interior Ethan Allen Hitchcock to stop the allotment of the Reservation. Lone Wolf argued that the allotment was a denial of due process and a violation of the consent requirement in the Medicine Lodge treaty. The federal government’s lawyers asserted that Congress had a right to alter the terms of the treaty through legislation, because it had paramount authority over Indian affairs. Justice A.C. Bradley of the Supreme Court of the District of Columbia rejected the Kiowa claim that the 1900 Act deprived tribes of due process. He stated that lack of consent was not relevant because Native American matters were under the exclusive control of Congress. The Court of Appeals upheld Bradley’s decision, and the United States Supreme Court agreed.

Justice Edward Douglas White’s opinion stated that Congress had the right to alter the terms of treaties with Native American tribes, because “authority over the tribal relations of the Indians has been exercised by Congress from the beginning, and the power has always been deemed a political one.” The judiciary could not interfere in Congress’s “plenary power.” This decision was based on the idea that Indians held dependent status to the United States government. Calling Native Americans “the wards of the nation,” White stated that “from their very weakness and helplessness, so largely due to the course of dealing of the Federal government with them and the treaties in which it has been promised, there arises the duty of protection, and with it the power.” This assertion of paternal dominion over Native Americans reversed the Supreme Court’s acknowledgment of a certain measure of Indian autonomy in previous cases, such as Worcester v Georgia 31 U.S. (6 Pet.) 515 (1832). Shortly after the decision, the U.S. opened Kiowa lands to white settlers, and over 50,000 settled on the “surplus” lands that Kiowa and Comanche had possessed under the Medicine Lodge Treaty. The “plenary power” doctrine first affirmed in Lone Wolf v Hitchcock is still valid Indian policy today.