In a sign that Republican kingmakers may be gravitating towards Rick Santorum, the National Review's editors urged Newt Gingrich to drop out of the Republican presidential race and throw his support to Santorum.

Like many other conservative commentators, the influential National Review has made no secret of its distaste for Gingrich. The editors also exhorted the former Speaker to end his candidacy in a December editorial that said Gingrich's flaws -- his impulsiveness, his grandiosity, his weakness for half-baked (and not especially conservative) ideas -- could cost Republicans the election.

The dynamics of the race have shifted significantly since then. Gingrich silenced some of his critics with a convincing win in the South Carolina primary, but his campaign has foundered since. After resounding wins in Missouri, Minnesota and Colorado,  Santorum has worked to supplant Gingrich as the conservative alternative to Mitt Romney, and the National Review decided to lend a hand.

Review: Gingrich Is Persistently Unpopular

In an editorial entitled Santorum's Turn, the editors wrote that Santorum was overtaking Newt Gingrich as the principal challenger to Mitt Romney and said Gingrich should exit the race and endorse Santorum.

Gingrich's verbal and intellectual talents should make him a resource for any future Republican president, the editors wrote. But it would be a grave mistake for the party to make someone with such poor judgment and persistent unpopularity its presidential nominee.

The editorial stopped short of endorsing Santorum outright, but it articulates a now familiar sense of discouragement with Romney's uninspiring candidacy. Calling Romney a transactional politician rather than a charismatic one, the editorial offers the former Massachusetts governor some campaign suggestions before taking a swipe:

Republicans, even the many who are well disposed to [Romney], have been saying as loud as they can: It isn't enough.