Republican former Gov. Mitt Romney of Massachusetts has not yet endorsed a candidate for the 2016 race for the Republican nomination, despite a report from The Huffington Post on Feb. 21 that Romney had planned to endorse Sen. Marco Rubio of Florida some time in the days leading up to Nevada's Republican caucus.
Despite the lack of an immediate endorsement before the caucus on Feb. 23, Rubio would seem to be the logical candidate for Romney to support given his reputation as a firm member of the Republican establishment and because Rubio now appears to be the inevitable "establishment pick" against Sen. Ted Cruz of Texas and businessman Donald Trump.
Over the course of the election season, Romney has not exactly had the best of relations with either Cruz or Trump, according to Boston.com. Romney has previously unloaded on what he believes are Trump's "nonsensical" proposals on foreign policy, while Cruz has slammed Romney over comments he made regarding the 2015 Iranian nuclear deal.
Romney has previously indicated he would wait to endorse the eventual nominee if it ended up being someone with views mostly palatable to his. With an increasing acknowledgement by senior Republicans that Donald Trump is, in fact, the front-runner of the race, there's little doubt Romney would prefer to endorse Rubio.
Such an endorsement is likely forthcoming even if both Romney's and Rubio's representatives deny it now. With former Gov. Jeb Bush of Florida out of the race, the eventual candidate of the Republican establishment will be looking for Romney's endorsement.
As of January 2015, Romney had the enviable distinction of being viewed positively by 52 percent of Republican voters, according to The Wall Street Journal. Rubio maintains a favorability rating of around 35-36 percent in recent polls, according to The Huffington Post.
An endorsement by Romney would be highly likely to curry a lot of support from non-Trump, non-Cruz voting Republicans who have previously been spread among several different candidates.
So what is the unknown factor here? The answer is Gov. John Kasich of Ohio. Kasich remains a thorn in the side of GOP donors who want to start coalescing support behind one candidate before it becomes too late to stop Trump.
Kasich wants to remain in the race at least until the Ohio primary, on March 15, which makes the task of uniting the various sectors of the Republican establishment more difficult.
A Romney endorsement of Rubio would be a shot in the arm to the Republican establishment in a race which has so far seen establishment candidates rejected by the voters at almost every turn. It appears inevitable that Romney will eventually support Rubio, but the question of "when" is a critical one which could have lasting implications on the shape of the race going forward.