The king’s heart is in the hand of the Lord as the rivers of water. He turneth it whithersoever He will.” – Proverbs 21:1
God can change a ruler, God can remove a ruler, and God can overrule a ruler.
You ask, “Should I pray for my leader if he’s wicked?” You ought to pray all the more for him. Why? Because the Bible says, “I exhort therefore, that first of all, supplications, prayers, intercessions, and giving of thanks be made for all men; for kings and for all that are in authority, that we may lead a quiet and peaceable life, in all godliness and honesty. For this is good and acceptable in the sight of God our Savior.” – 1Timothy 2:1-3
The greatest responsibility in America is not in the White House but in the church house. We’re to pray for our government. Pray for those who are in authority.