It’s hard to define Florida Senator Marco Rubio’s role in the effort to craft a comprehensive immigration reform bill. Rubio has presented himself as an indispensable figure, key to moving a proposal out of the Senate and onto the House floor. But the outcome of the 2012 election guaranteed a GOP push for comprehensive immigration reform as a way to stem their bleeding with Latino voters — Rubio or no Rubio.

What’s more, Rubio’s stated support for reform is belied by his constant search for escape hatches. Earlier this year, he claimed the Obama administration’s leaked immigration proposal threatened the prospects for reform, despite its similarity to his framework. Over the weekend, after labor and business groups reached a deal on guest workers, he demanded the Senate slow the process down. Rubio claimed that “excessive haste in the pursuit of a lasting solution” is “dangerous” to the “goals many of us share.”

Democrats aren’t trying to rush the bill. But this hasn’t stopped Rubio from issuing a threat to kill it if the Senate doesn’t hew to his preferred process.

One interpretation of this behavior is that Rubio is sincere in his calls for comprehensive immigration reform, but he doesn’t want to alienate Tea Party conservatives who are hostile to the idea. This is how Politico describes the dynamic: “Even if Rubio winds up signing on to the deal, he knows that selling it to hardcore conservatives will be a huge project.” Why? Because there’s little chance the base will embrace a deal supported by President Obama and the Democratic Party.

This isn’t just illustrative of the dilemma Republicans find themselves in with regards to immigration — that GOP elites want a policy that’s opposed by their base. It’s also an excellent demonstration of the key problem facing Washington: Namely, that there’s almost nothing President Obama can do to preclude opposition from House Republicans. Indeed, pundits should keep this in mind the next time they demand ill-defined “leadership” from Obama: By simply participating in the effort to craft comprehensive immigration reform, Obama has endangered it.

The same could be said for any number of issues. Yes, many Republicans have a principled opposition to new gun control laws, but there’s no doubt that some of the intense opposition to uncontroversial proposals — like universal background checks — is driven by the simple fact of Obama’s support.

If Rubio is serious about immigration reform, than his threats to kill the bill are an attempt to circumvent this dynamic. As Greg wrote yesterday, “He needs to reassure conservatives that he’s prepared to walk away from any deal, and that he’s getting them everything he can in the process.”

For Republicans concerned about the future of their party, the fact that Rubio has to do this dance should worry them. When a large portion of the GOP refuses to work with the other side, this sharply limits the opportunities for constructive, politically palatable legislation.

Conservatives didn’t like the McCain-Feingold campaign finance law or No Child Left Behind, but when elections came, these legislative initiatives gave bipartisan credibility to Republican candidates. By precluding the possibility for anything like these laws, conservative Republicans are ensuring difficulty for the next round of presidential candidates. Substance is important, but so is winning.

Jamelle Bouie is a staff writer at The American Prospect, where he writes a blog.