These verses from the book of Psalms make a great prayer for America.
8O remember not against us former iniquities: let thy tender mercies speedily prevent us: for we are brought very low. 9Help us, O God of our salvation, for the glory of thy name: and deliver us, and purge away our sins, for thy name's sake...
13So we thy people and sheep of thy pasture will give thee thanks for ever:
we will shew forth thy praise to all generations. Psalm 79:8,9,13