Marco Rubio's chances of winning the GOP primary have doubled since the last debate

Marco Rubio campaigning in Iowa. — (Image credit: David Greedy/Getty Images)

Back when Scott Walker was still in the race and Jeb Bush seemed like the GOP's strongest contender, Marco Rubio, as The New York Times puts it, "looked boxed out." But now that Walker has thrown in the towel and Bush is struggling, Rubio may finally be getting his big chance — and the betting markets are paying attention. Since the last Republican debate, The New York Times reports that Rubio's chances of winning the nomination have more than doubled, jumping from 13 percent to 29 percent. That puts him only two percentage points behind Bush, at 31 percent.

But even with the window wide open for Rubio, The New York Times writer Nate Cohn wonders if the 2016 hopeful can take advantage. Rubio's widespread appeal is a double-edged sword, Cohn suggests, since he "is not the natural favorite of any wing of the party, which is the easiest way for a candidate to become the first choice to a meaningful block of voters." As a "young, Catholic, Latino lawyer from Miami," Rubio might also struggle to appeal to "old, evangelical, white, less-educated, and rural voters," Cohn writes.