America's need to repent requires nothing more than removing the evil-doers from gummint. A task perhaps more difficult than a one-time trip to the polls. But as you will probably agree, it's kinda hard to drain the 'swamp' when the alligators are nipping at your knee-caps. Let's move the alligators out to a happier hunting ground and then we can purify the waters of gummint. As it is, our energies and priorities are divided.
Concerning personal 'sins', apart from the shortcomings of gummint, people tend to purify themselves when they are looking for change within themselves and can see examples of how they want to live and respond to life. Those examples, as we know, have always been before their eyes, but they have not eyes to see as yet. But thank God for His Amazing Grace.
I believe that prayer will eventually break the back of Islam and it will only be eliminated when these people see the one true God (and it's not ALLAH!).