Senior Republican senators who’ve clashed with Cruz for years have had nothing but nice things to say about Rubio even as he’s dissed — and largely ditched — his day job in the Capitol. Just this month, Rubio has racked up endorsements from nine members of Congress, compared with two for early GOP front-runner Jeb Bush. More House endorsements for Rubio are set to roll out in December, according to campaign sources, and several GOP senators said privately they expect their colleagues to get behind Rubio once the GOP field thins.

The movement toward Rubio appears to be as much about anxiety over the possibility of Cruz going up against Hillary Clinton as it is affection for the Florida senator. The idea of Cruz as the nominee is enough to send shudders down the spines of most Senate Republicans.

Mainstream elected Republicans now see Cruz as a bigger threat than Donald Trump or Ben Carson to clinch the nomination — but equally damaging to their party’s chances of winning the White House and keeping the Senate next fall. Rubio would be a much stronger general election standard bearer, they believe…

But Senate Republicans who are subtly rallying behind Rubio are also thinking about their own power. With the GOP defending a slim Senate majority next year, lawmakers want a nominee who can win over moderate voters in battleground states. They don’t say explicitly that means Rubio, but in a two-man race, their preference isn’t hard to detect.