Rep. Paul Ryan (R) of Wisconsin inserted himself Sunday into what could be possibly one of the the more remarkable debates ever to hit Capitol Hill.

Speaking on CBS's "Face the Nation," Representative Ryan said he was not in favor of shutting down the government as a way of forcing Democrats to repeal President Obama's health-care law – a political tactic some Republicans, such as Sen. Ted Cruz of Texas, have advocated. Instead, he said "there are more effective ways of achieving that goal" – though he was not asked to name any.

What is remarkable about the debate is that Democrats aren't going to repeal Obamacare. Ever. Nor does the Republican Party have any conceivable political lever to make them do so. A government shutdown will not defund Obamacare, nor will it likely change anyone's opinion about it.

And yet many Republicans are undaunted – and with good reason.

More than the debt-ceiling debate of 2011 or this year's angst over the sequester, the current talk of resorting to a government shutdown to defund Obamacare speaks to the changing character of Capitol Hill.

What has changed is the calculus of congressional politics.

The legislative process has always been about numbers. Generally, the numbers that have meant most are vote counts – does a bill have the votes to pass? Party leaders were voter-herders – astute in measuring support for a bill and sometimes artful in their ability to navigate it to passage – and their party whips helped make sure the cattle stayed in line.

There are those in Congress who still play by these rules, House Speaker John Boehner of Ohio and Senate minority leader Mitch McConnell of Kentucky among them. But the new breed of legislator puts a different number first.

Senator Cruz hinted at this new math in speaking about repealing Obamacare to Young Americans for Liberty in Arlington, Va., Wednesday.

"Right now, we don't have the votes.... I'm going to be perfectly candid, we can't win this fight," he told the 300 libertarian students. "The only people who can win this fight are you. The only way we win this fight is if the American people rise up in overwhelming numbers and demand our elected officials to do the right thing and stand for principle."

Despite Cruz's plea, demographics suggest Young Americans for Liberty and like-minded voters can't change Congress enough to make a repeal feasible. There just aren't enough of them. But demographics do suggest that they can play a decisive role in determining their next Republican candidate for Congress during the 2014 primaries.

And that is the math that fuels Cruz – or at least ensures that his shutdown-the-government views must be taken seriously by the Republican establishment (a.k.a. those still playing by the old rules). The political polarization of America has, particularly among Republicans, replaced the old bean-counters with ideologues who are less interested in vote counts than standing fearlessly for their constituents' demands, even if that is at odds with legislative realities.

Cruz and his cohorts are simply seeking any legislative means at their disposal to do what the voters who elected them desperately want them to do: end Obamacare. The fact that there are no viable legislative means at their disposal is less important than the attempt, because in their states, the Republican primaries virtually decide the winner, and failure in a noble cause is seen as better than accession to a hated one.

With voters in red states by all appearances angrier than voters in blue states, the race to the right has become a mad dash, and Cruz is leading the pack.

What makes life hard for Ryan is that he sits somewhere in the middle. His views on strict financial austerity elicit cheers from the ideologues. Yet he is also part old school, using his position as House Budget Committee chairman as a bully pulpit from which to try to move the Congress rightward and toward greater acceptance of his ideas on entitlement reform.

He is an ideologue with real power, and therefore must tread carefully or risk losing either his clout or his aura.

What makes Washington watching so fascinating (if harrowing) at this moment, is that no one really knows which way this will go. Tea party Republicans in the House brought the nation to the brink of a debt crisis in 2011 – and feel they have only the sequester to show for it. For legislators who wanted major entitlement reform, that is a disappointing return.

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The House's 40 (failed) attempts to kill Obamacare underscore the stakes as Republicans see it. If, instead of entitlement reform, we simply get another entitlement, the die will be cast and America will be put on the path to becoming another Greece, living far beyond its means thanks to programs imposed upon the people by a massive and expanding government. Liberty will be dead. And the economy won't be far behind.

To ideologues, those are fighting words.