Some Stuff I Just Don't Get!

Here is a hunk of Scripture that just makes no sense to me at all. 

Romans 13:1-4(NKJV)

1Let every soul be subject to the governing authorities. For there is no authority except from God, and the authorities that exist are appointed by God. 

OK, I get that.

2Therefore whoever resists the authority resists the ordinance of God, and those who resist will bring judgment on themselves. 

3For rulers are not a terror to good works, but to evil. Do you want to be unafraid of the authority? Do what is good, and you will have praise from the same. 

4For he is God’s minister to you for good. But if you do evil, be afraid; for he does not bear the sword in vain; for he is God’s minister, an avenger to execute wrath on him who practices evil. 

This part all makes sense regarding Godly leaders.  But what about leaders like Hitler, Stalin, Idi Amin, Pol Pot, and others who have murdered and tortured millions of their own citizens? 

The above Scripture seems to make the assumption that all leaders are good leaders.  It doesn't seem to make any provision for ungodly and evil leaders.  I find it hard to believe that God is going to be terribly upset with anyone who helped topple Hitler. 

I think this might be part of why I have more trouble with Paul's writings than any other part of the Bible.