As other posters have noted, should Republicans win back control of the senate in 2014 (and retain their majority in the House), that could change. Even then, wimpy Republicans cannot necessarily be counted on to do the right thing as they know they'll be incessantly accused of 'racism' by the left and targeted for defeat in their next election race.
So, when I read about impeaching Obama I tend to sigh and roll my eyes, thinking that 'in a perfect world...' but then I open them and see we're living in a decidedly imperfect world where the most radically leftist man in the U.S. senate was twice elected to the most powerful position in the world. God help us.
The issue for me is that we are rapidly reaching the point where impeachment is demanded not merely by expediency but also by justice.
I would be embarrassed if the party that nominally represents my interests in Congress refused to act on that basis.