The final four Republican presidential candidates debate tonight in Tampa, starting at 8 pm central time on NBC. Mitt Romney will try to keep the focus off his own finances, having promised to release two years of tax returns tomorrow. Romney may also be more aggressive about drawing contrasts with Newt Gingrich, judging from a new Romney tv ad I’ve posted after the jump.

In the latest Republican debates, Ron Paul criticized Gingrich and Rick Santorum repeatedly, while mostly ignoring Romney’s record. I expect him to stick to that plan, which has a double benefit: it keeps Paul on good terms with the most likely GOP nominee while undermining his rivals for the “not Romney” vote.

I assume abortion will be a significant topic tonight, in light of the 39th anniversary of the U.S. Supreme Court’s Roe v Wade decision. I don’t know what more the candidates can say on the subject, which has been explored in several previous debates.

Any comments about the debate or the GOP campaign generally are welcome in this thread.