Only a few months ago, Sen. Marco Rubio (Fla.) was cruising toward the 2016 Republican primaries.

Yet Rubio's stock took a major blow when the freshman senator championed immigration reform, and he only worsened the slide by swinging right and endorsing the government shutdown. Now way behind in horse race polls and overshadowed by other GOP hopefuls on both his left and right, Rubio has a delicate balancing act ahead as he tries to haul himself out from the morass.

Rubio's aggressive promotion of immigration reform was a bold gamble, but one that didn't go over well with his party's base. In an apparent attempt to rectify the damage, Rubio leapt on the shutdown bandwagon. But the sudden shift, from deal-making centrist to right-wing ideologue, struck many observers as a blatant, calculated attempt to win back lost support. Rubio had "lost control of his message" during the immigration debacle, Matt Lewis wrote in The Week, so "like a man skidding on ice, he overcorrected."

"When you try to please everyone, you end up pleasing nobody," he wrote.

In trying to play both sides, Rubio tripped into the same trap that ensnared Mitt Romney in 2012. Romney vacillated between being a "severe conservative" and the guy who gave Massachusetts universal health care, ultimately failing to sell the public a definitive image other than that of a very wealthy politician who speaks out of both sides of his mouth. Rubio hasn't quite reached Romney levels of flip-flopping, though he risks owning that comparison should he continue to leap from one pole to the other.

Adding to his dilemma, Rubio is no longer the most visible 2016 aspirant from either wing of the GOP. Sen. Ted Cruz (R-Texas) has seized the Tea Party mantle, while New Jersey Gov. Chris Christie further cemented his position as the pragmatic moderate this week by dropping a challenge to same-sex marriage in his state. Rubio's problem is reflected in polls of the 2016 GOP primary, which put Cruz and Christie at or near the top, with Rubio, who led such surveys earlier this year, somewhere in the middle of the pack.

But it appears Rubio may have hit upon a solution: A careful creep back toward the center.

Republicans have cited the ObamaCare website's glitches as proof the whole law is a disaster, though they've not suggested concrete remedies aside from a repeated insistence that the law must be scrapped. Rubio, taking a different tact, introduced a bill this week to delay penalties for people who don't obtain insurance — a position even the administration admitted it may have to take should the problems persist.

"It's unfair to punish people for not purchasing a product that they can't purchase right now because the technology that's in place, the website they're supposed to buy it on — by the president's own admission — is not working," he said.

The move is a notable shift from the shutdown rhetoric, when fire-breathing conservatives aimlessly attacked ObamaCare despite having no realistic strategy. The defund effort was "not a plan to achieve a defined legislative end," wrote New York's Jonathan Chait, but rather "a demonstration of dissent from a political faction that has no chance of winning through regular political channels."

Rubio, by contrast, has now offered a concrete goal that could win bipartisan support, without straying from the anti-ObamaCare camp. At the same time, he's walked back his past support for the shutdown, claiming, however falsely, he never wanted it in the first place.

Rubio cannot out-Cruz Ted Cruz. He cannot remain above the GOP fray, a la Christie. But his latest proposal shows that, in some instances at least, he can use the Senate to create a platform that deftly balances the competing claims of his party.