How could a Christian nation practice sin?

Those who say that America was founded as a Christian nation, and that God has taken an active role in the history of our nation, often have difficulty explaining the treatment of Native Americans and the institution of slavery. How could God be involved with a nation that mistreated the original inhabitants of America, and how could God bless a country that actively supported the slave trade? There are no easy answers to those two questions. Obviously God does not condone needless war, breaking treaties, or one group of people owning another. There are two ideas that I have come across over the years that helped me in this matter. The first principle was that we can never judge one generation by our own standards of conduct. Many things that were done hundreds of years ago seem unacceptable by our way of thinking, but were generally accepted by those who lived in that time period. Slavery was a practice that had been accepted for thousands of years. When nations conquered other nations, it was common practice to place the vanquished into the bonds of slavery. When our founding fathers brought the first slaves to America in 1619, it was nothing out of the ordinary. Christians at this time also drank beer, and began smoking tobacco. Today if a Christian practices any of these behaviors, their commitment to Christ would be questioned. This does not justify the practice of slavery, I believe God judged America with the Civil war for their treatment of slaves, but it does help us at least to understand how a man like Thomas Jefferson owned slaves, even though he wrote that all men are created equel. That brings us to the second principle, and that is that all Providence can be put into two categories, mercy of judgment. Many times we think that God only intervenes to help out nations or individuals. However, God often judges men for their sin and selfish behavior. When we say that America was founded as a Christian nation, it does not mean that everything that was done by our founding fathers was right. The treatment of Native Americans of breaking treaties and sending them off to other land was wrong. God judged America with many wars and destruction of property and life. The War of 1812 was partially caused by Indian resentment. The wars in the West from 1870- 1890 were direct results from our unjust treatment of Indians. As was mentioned the Civil War was mainly caused by our failure to end slavery by laws. The civil rights struggles that started in 1950 and still continue today, remind us of the evils of slavery that were tolerated in America for so long. God never condones sin, but He often uses its results to bring about His will. We need to learn from the mistakes of the past, and make sure we do not allow race to continue to be an issue of fear and hatred today. God is often merciful to us and provides victory and peace, but He also judges sin and allows suffering and war. May God have mercy on us and our nation.