Frum advises Newt to drop out and hope for a Romney defeat:

If the GOP were to lose in 2012, the next cycle could be the most wide open since 1940. There would be no "runner-up" to claim the nomination next time, the way Romney claimed it in 2012 or John McCain in 2008 or Bob Dole in 1996 or George H.W .Bush in 1988. But a Gingrich who had won some primaries as a conservative alternative to Romney — something neither Rick Perry nor Sarah Palin nor, by the way, Ron Paul or Rick Santorum will have done — could plausibly claim leadership of the conservative wing of the Republican Party. Such a Gingrich could then credibly demand kowtowing and ring-kissing from everyone entering the huge 2016 field, especially since, by that point a year older than McCain was in 2008, he'd have difficulty mobilizing support for a second run of his own.