Sens. Marco Rubio (R-Fla.), Ted Cruz (R-Tex.) and Rand Paul (R-Ky.) are fighting a losing battle to defund Obamacare that is going nowhere fast on Capitol Hill.

And yet, they each stand to gain politically from the crusade that is doomed to failure in part because, well, it is doomed to failure.

Why? Because Rubio, Cruz and Paul get to champion a plan that looks attractive to many conservatives in theory but could be politically disastrous in practice.

The trio of senators and possible 2016 presidential candidates is supportingpitch circulated by Sen. Mike Lee (R-Utah) that calls on lawmakers to not support any continuing resolution or appropriations bills that devote even a cent to funding President Obama's health-care law. The plan has gained very little traction in the GOP Conference, despite a series of campaign-style events in August designed to build support for it.

Still, it's getting the job done for the principals involved. Politically, at least.

Cruz has quickly made it clear that he wants to be an uncompromising, pure conservative who doesn't play ball with the establishment and doesn't get outflanked on the right by anyone. This is right up his alley.

Bruised by his push to pass a comprehensive immigration bill, Rubio is looking to reinforce his standing among conservative activists. Joining the Obamacare fight is yet another way for him to do that, in addition to speaking out on an issue his allies insist he cares about a great deal.

Finally, Paul's participation means he doesn't get outflanked by either Rubio or Cruz on Obamacare. And the campaign-style effort behind the push (Paul, Lee and Cruz are headlining a rally on Capitol Hill on Sept. 10) is a venue for all three to continue talking about their opposition to the law.

Of course, those potential political benefits must be weighed against the risks of the plan the senators are touting. The current continuing resolution to fund the government expires on Sept. 30. So, Congress must pass a new one to keep the government running starting Oct. 1.

If enough Republicans joined Lee and his supporters they could prevent Congress from passing a bill that included funding for Obamacare, which could lead to a government shutdown. And potentially triggering a government shutdown is a very politically perilous proposition that risks major backlash and blame directed at the GOP, and more specifically those in the party who are responsible for such an occurrence. Even among the most conservative elements of the party, a sense of buyer's remorse could kick in if the backlash is strong enough.

But given that the plan has virtually no chance of passing, those concerns have been rendered more or less irrelevant to the discussion at hand. And that's when a losing proposition begins to look like a winning hand, in at least some respects.

If, as expected, the Lee plan continues to go nowhere, what Rubio, Paul and Cruz can all basically say about their fight against Obamcare is, "Hey, we gave it our all on this crucial issue." And that's a powerful argument to make to the most conservative part of the electorate that already has deep distrust for the Republicans and Democrats who don't support the push to defund Obamacare. It's also a powerful argument to make a in GOP presidential primary in which candidates often jockey for the conservative high ground.

The reality is that Obamacare almost certainly won't be defunded the way Paul, Cruz and Rubio want. But don't automatically pencil them into the loser's circle as a result.