He should not be impeached because of DOMA. He should be impeached because he has abused his office by declaring it unconstitutional. That decision belongs solely to the SCOTUS.
The repeal of DOMA by executive fiat (not even executive order) is just an example of a bigger problem, that being the blatant disregard of separation of powers. All instances where he has disregarded court rulings, two being the health care challenges and offshore drilling, should be included as grounds for impeachment as well. Barry Dunham is a wannabe Hugo Chavez.
“That decision belongs solely to the SCOTUS.”
I agree! Obama is in contempt of court there, in addition to going ahead with Obamacare after that was declared unconstitutional, rather than delay implementation pending Supreme Court review.