With Bush’s early electability argument thrown into question, it’s become fashionable among political pundits to anoint Rubio as the replacement front-runner. “The entire commentariat is going to feel a little silly when Marco Rubio wins every Republican primary,” conservative New York Times columnist Ross Douthat tweeted last month. Vox’s Matthew Yglesias mischievously called on Bush to drop out of the race entirely to clear the path for Rubio, who he described as “Jeb Bush but good at politics.”
As Yglesias alluded, the biggest reason Rubio is such a threat to Bush is the same reason he threatened to crowd the senator out of the race before it began — their campaigns have a tremendous amount of overlap. Both are running on platform of wooing big business and middle class voters with budget-busting tax cuts —their plans have each been estimated to cost $3 trillion to $4 trillion — as well as on education reform and returning the country to a hawkish foreign policy. Both are relative moderates within the party on immigration and both court Latino voters in fluent Spanish…

That’s the good news for Rubio. The downside is that the Rubio boomlet is still less about any spectacular surge on his end and much more about other candidate’s failures. He’s the most consistent campaigner in the race, but he isn’t someone like Barack Obama in 2008, who inspired a rabidly devoted core following and drew large crowds long before he overtook Hillary Clinton in the polls. Rubio’s reception in Iowa was warm enough, but voters rarely seemed fired up.  

Rubio also still lags behind outsiders Trump, Carson, and Fiorina in most polls, averaging around 9.5% support. If history serves as a guide, it’s unlikely any of those three rivals will end up as the nominee given their political inexperience and lack of elite party support — but a lot of predictions have already gone awry this year and Rubio will have to make his move at some point.