Here is how to pray for President Obama on this issue:

Proverbs 16:12
It is an abomination to kings to do evil,
for the throne is established by righteousness.

Proverbs 20:28
Steadfast love and faithfulness preserve the king,
and by steadfast love his throne is upheld.

Proverbs 21:1
The king's heart is a stream of water in the hand of the Lord;
he turns it wherever he will.

Proverbs 21:3
To do righteousness and justice
is more acceptable to the Lord than sacrifice.

Proverbs 21:21
Whoever pursues righteousness and kindness
will find life, righteousness, and honor.

Proverbs 24:21
My son, fear the Lord and the king,
and do not join with those who do otherwise

Proverbs 25:5
take away the wicked from the presence of the king,
and his throne will be established in righteousness.