Former Florida Gov. Jeb Bush's decision Saturday to drop out of the Republican primary frees the 6 percent of support he holds nationally -- not an insignificant amount in a GOP race that remains deeply fragmented.
One theory of this year's election holds that the Republican field is divided between an "establishment lane" and an "outsider lane," with voters gravitating either toward the bloc of traditional politicians like Bush, Sen. Marco Rubio (R-Fla.) and Ohio Gov. John Kasich, or else to more disruptive figures like Donald Trump, Ben Carson and Sen. Ted Cruz (R-Texas). That would make Bush's departure a serious boon to the Rubio campaign.
The reality, polling suggests, is a little more complicated.
Recent NBC/SurveyMonkey polling shows Rubio as the most popular second choice for Bush supporters, but it's far from unanimous.
Combined data from the four most recent Economist/YouGov polls show slightly more significant support for Rubio, giving him 23 percent, followed by Kasich at 12 percent, Cruz at 11 percent, Carson at 10 percent, and the remaining candidates in the single digits. Since the polls date back through the beginning of the year, they also include some candidates who have since dropped out, such as New Jersey Gov. Chris Christie, who attracted 11 percent while he was still included.
Forecasts about Trump's demise tend to rely on the idea that, as some of his rivals drops out, the remaining challengers will consolidate support. While there's still evidence that Trump may have a ceiling to his support, it's not at all clear that he's reached it yet -- or that Rubio will get the boost he's hoping for out of the narrowing field.
This post has been updated to include YouGov data on likely Republican primary voters.