So did Arizonan Jeff Flake, but the marquee names here obviously are the last two GOP nominees for president.

Ramesh Ponnuru asks a good question:

Yeah, that’s … interesting. Everyone can understand why a gay-marriage supporter would oppose the bill and everyone can understand why a gay-marriage opponent would support it. You can also understand why someone would support both: Gays should be free to marry and religious believers should be free not to accept an offer to provide services to them. Accommodation and MYOB coexistence, libertarian-style. The fourth position, though, where someone opposes gay marriage but also opposes letting believers decline service is less obvious. Could be that McCain and Romney simply think the bill’s overbroad; they might be fine with a bill that granted a religious exemption from serving at a gay wedding specifically, but they can’t condone one that would let people refuse to serve gays under any circumstance. Or maybe both of these guys, as centrist Republicans, are more supportive of legal gay marriage than they’re letting on and simply haven’t, er, come out yet.

Actually, skip to 1:20 below and you’ll see that neither is true in McCain’s case. He’s brutally frank about why he opposes the bill: The boycotts that ensue could damage Arizona businesses, and right now there’s no stronger Republican champion of business, both in Arizona and elsewhere, than John McCain.