Comparing himself to McCain, Thompson and Giuliani on the gay marriage amendment as the only one who is for it but he leaves out Huckabee (who is also for it):

For the first time, Mitt Romney is using direct mail to contrast his record with his GOP rivals. In a piece that has just hit Iowa mailboxes, Romney points out that he’s the only of the “leading Republican candidates” to support a constitutional ban on gay marriage.
The former governor pointedly ignores Mike Huckabee, who has emerged as his most serious challenger in the Hawkeye State and who supports the ban.
Romney, whose campaign has debated internally whether or not to draw such direct contrasts with paid media, is clearly trying to set himself apart as the only electable candidate who sides with the conservative GOP base on a key issue.
The piece, sent by a rival campaign, is the classic “side-by-side,” used to paint a rival (or rivals) as being on the unpopular side of a policy. Unsaid, of course, is that Romney himself took a much more moderate approach to gay rights issues when he ran for the Senate in 1994 and governor in 2002.

(via)
If I were a presidential candidate in this race I would do a comparison mailing on Romney running for governor of MA and running for president today.
BTW, it still irks me that this has become such a big issue in the race when Romney can’t even do anything about it if he were elected president. It’s not going anywhere so give it up as an issue, people. It doesn’t belong in the presidential race, make it an issue where it will count, in a congressional race.
Why don’t you tell us where you stand on drilling in the Gulf or ANWR, that’s more important to me. Why don’t you tell us what you plan to do about the value of the dollar? Iran? Israel? The deficit, pork filled spending bills? Shrinking the size of government? These are actually issues that the president will be able to do something about. Stop wasting our time on issues that don’t really matter.
If the gay marriage amendment comes up tomorrow night, I hope the candidates turn to Romney and say, “Since you’re for it, tell us how you’re going to make it happen.” It’s easy to be for something now that you know won’t be going anywhere later.

I think it’s commendable that the other candidates aren’t pandering on this issue just to get more votes, it makes me respect them more.