Why Is America Blessed?

I've been pondering if I should title this entry, "Does America Have The Moral Ascendency To Be the World's Police Dog?"
I am reading a book about Tulsa riot where the white mobs attacked the town of Greenwood. Greenwood's inhabitants are black. It occurred in early 1900s.
The book gave a good view of what's happening in that era. The Ku Klux Klan. The lynchings of blacks by whites simply because blacks were accussed of assaulting (rape during that time are called assault) white girls. The discrimination against Jews, immigrants, catholics and colored people. I was even aghast because according to the book the White Americans, during that time, perceived blacks as sexual maniacs (which I am sure is totally wrong) who when they see white girls will do everything to lay on them.
I can't help but recall what Americans did in my own country. The Americans used to have military bases. (Which I feel were the bases of our insecurities) Some American GIs shoot scavengers in the dump simply because they mistook filipino scavengers as wild pigs. (This was immortalized in the film "Minsan May Isang Gamo-Gamo" starring Nora Aunor.
I can't help but recall what the Americans did to American Indians when they displaced them.
I can't help but recall what the Americans did to Hiroshima and Nagasaki which killed thousands of innocent civilians all in the name of democracy.
I can't help but recall the tv footage that I saw on tv when white policemen were beating black suspect.
I can't help but recall what happened in Guantanamo Bay when American soldiers humiliated Iraqi POWs. They stripped Iraqi POWs and asked them to do sexual acts.
Knowing all these, is it hard to speculate what's happening in Iraq now?
I am asking God, "Are you turning your eyes away from the evil which Americans are doing? I know vengeance is not ours but why are you blessing the perpetrators of evil?"
With this I can't help but to be cynical