Tea Party diehards, led by Canadian-born Texas Senator Ted Cruz, seem certain to lose the current fight to defund Obamacare.
But losing that battle may advance the new right's struggle for the soul of the 21st-century Republican Party.
They "really should be called not the Tea Party Right, but the Newest Right," said Michael Lind, co-founder of the New America Foundation, a non-partisan public policy institute in Washington.
That the liberal elites tend to dismiss them them as ignorant extremists, he added, is snobbery and shows a lack of understanding about the shifting political spectrum.
Polls show that most Americans blame Republicans in general rather than the Tea Party in particular for the political standoff that has left the federal government partially shut down for nearly two weeks. And even as some party heavyweights openly voice bitter frustration with Mr. Cruz, the Tea Party may be playing a long game. The race for the Republican presidential nomination in 2016 is under way.
In Mr. Lind's view, the "newest right" are "the mainstream right … they are the real power." And it would be a serious mistake to underestimate them.
"The American centre-left, whose white social base is among highly educated, credentialed individuals like professors and professionals, repeatedly has committed political suicide by assuming that anyone who disagrees with its views is an ignorant 'Neanderthal,'" he wrote in a recent essay for Salon.com.
An Associated Press-GfK poll released Wednesday showed that Republicans in general, but not the Tea Party, are taking the biggest share of the public's blame for the impasse.
And, rather than a malcontent fringe, the poll showed the Tea Party as a powerful and polarizing force among Republicans. More than four in 10 Republicans identified with the Tea Party and were more apt than other Republicans to insist that their leaders hold firm in the standoff.
The Tea Party has already shifted the political centre. If so-called moderate Republicans are acting – or not acting – out of fear of primary challenges from the right, Mr. Lind said, "that suggests the moderate wing of the Republican party is nearly extinct."
If that assessment is correct, then veteran moderate Republicans senators – like Kentucky's Mitch McConnell, the party's leader in the Senate; South Carolina's Lindsey Graham; and Tennessee's Lamar Alexander – may all be fighting for their political lives against Tea Party challengers.
What happens next will depend on whether the mavericks feel sold out in any deal that ends the current impasse, said Bill Whalen, a research fellow at the Hoover Institution, who has followed the rise of the Tea Party.
"They'll be mad, but do they choose to get even?" he said in an interview. "Getting even is going around America" and seeking to oust centrists in nomination battles where they believe "that the Tea Party was betrayed."
At the same time, new leaders, notably Mr. Cruz have emerged, winning both admiration and condemnation for this high-stakes, high-profile effort to wreck Obamacare. Some see it as self-promotion, others as a valiant principled stand. Either way, it may launch a presidential bid.
Mr. Cruz has also stayed solidly on message, championing a theme that portrays President Barack Obama as the problem – even as most Americans tell pollsters they blame Congress, and especially Republicans in Congress, for the impasse.
At least sometimes, rebelling against party orthodoxy can boost an ambitious politician.
In Politico commentator Rich Lowry said Mr. Cruz understands the long game.
"No one asked whether Ronald Reagan had successfully blocked the ratification of the Panama Canal Treaty in 1977 when he ran for president in 1980," Mr. Lowry wrote.
"For that matter, no one asked whether Senator Barack Obama had successfully defunded the Iraq War in 2007 when he ran for president in 2008, but in both cases they championed issues that were important to the party base."
For Democrats who believe that the surest route to that rarest of party objectives – 12 straight years of control of the Oval Office – is for the Republicans to pick a Tea Party darling as their nominee for president in 2016, Mr. Lowry's observation about Mr. Cruz's strategy may be sobering.
"Obama's example is instructive: When before have we heard of a new senator capturing the imagination of his party's base, establishing an unimpeachable standard of purity on a hot-button issue absolutely essential to it, and beginning to run for president shortly after arriving on the national scene?" he asked.