The Bible tells us specifically that it is one of God's jobs to promote certain people, according to His choosing, and to bring others down. Psalm 75:6-7 says, "For exaltation comes neither from the east nor from the west nor from the south. But God is the Judge: He puts down one, and exalts another."
Therefore, when you pray, ask God to raise up and bless every leader who suits His purposes for our nation--and to bring down every leader who does not.