To pray a Psalm of vengeance (Psalm 109)

First read this and look at the judgement called for by the Psalmist for his enemies (and read the rest of 109 if you have the time):

"Appoint a wicked man against him;
let an accuser stand at his right hand.  
When he is tried, let him come forth guilty;
let his prayer be counted as sin!  
May his days be few;
may another take his office!
May his children be fatherless
and his wife a widow!  
May his children wander about and beg,
seeking food far from the ruins they inhabit!  
May the creditor seize all that he has;
may strangers plunder the fruits of his toil!  
Let there be none to extend kindness to him,
nor any to pity his fatherless children!  
May his posterity be cut off;
may his name be blotted out in the second generation!  
May the iniquity of his fathers be remembered before the LORD,
and let not the sin of his mother be blotted out!  
Let them be before the LORD continually,
that he may cut off the memory of them from the earth!" - Psalm 109:6-15

The book I'm reading right now is about praying these Psalms, the conclusion being three fold:

1. Jesus was the one who prayed these Psalms
2. We need to pray for thanksgiving from the Lord for people who are saved
3. We also need to pray unbelievers will either be converted, or their plans will lead them to destruction and they will enter into judgement.

The arguments for 1 and 2 are not difficult to understand with some reading. But wrapping my head around praying for the judgement of my unbelieving friends is very difficult for me to wrap my head around.

Have you ever prayed for judgement for unbelievers? For example, look at Brian's recent post about praying for Myanmar (Burma). This book suggests we pray for people to be healed, helped and for the nation to be saved. But we also pray the leaders of the country will turn to the Lord and if they don't they will be brought into most terrible judgement.

We pray for their children to be fatherless. We pray the Lord will cut them off from the memory of the earth.

Can you pray like this? Do you agree with this? I'm still trying to digest a very well written argument with how it rubs me wrong. The books argument that its not always easy, but its Biblical, and we cannot impose our feelings on the Bible, but the Bible on our feelings.