At first glance, it would appear that the GOP's 11th-hour crusade against ObamaCare is alive and well.

The conservative group Heritage Action is launching a $500,000 ad campaign to persuade Republicans to pull out all the stops to defund the Affordable Care Act, President Obama's signature health-care law, before its key elements take effect. The group, the advocacy arm of the Heritage Foundation think tank, is also holding a series of town-hall style meetings to stir up anti-ObamaCare fervor.

The organizers are targeting 100 House Republicans who have yet to sign on to a defunding drive. But while Tea Party activists and a coterie of hard-core lawmakers are eagerly getting behind the effort, it appears that many within the party are resigned to defeat, particularly since the law will live on even if the GOP engineers a government shutdown.

"The Republican establishment doesn't have much appetite for a shutdown," says Jason Millman at Politico. "No matter how unpopular they believe Obamacare to be, they think history proves that a shutdown would be worse for the party."

Even some Republicans who have led the Tea Party charge are losing steam. Jamelle Bouie points out at The Daily Beast that Tea Party hero Sen. Rand Paul (R-KY) has suggested it's a lost cause, telling Fox News' Sean Hannity that he supports the defunding effort but "may not be able to guarantee victory." Sen. Richard Burr (R-N.C.) went a step farther last month, saying, "Listen, as long as Barack Obama is president, the Affordable Care Act is going to be law."

The dwindling of enthusiasm, Bouie says, is due to the fact the issue just isn't the ballot-box winner it once was for the GOP.

Tea Party Republicans had a huge hit with their rage against Obamacare. It gave them control of the House of Representatives in 2010, fueled their anti-spending crusade in 2011, inspired the most vocal of the GOP presidential candidates, and elevated a host of right-wing politicians to the Senate, providing a national platform for the crusade against the so-called government takeover of health care.

Hits aren't built to last, however, and after a while, this one began to fizzle. Mitt Romney's constant attacks on Obamacare did little to help his White House campaign, and few Republican Senate candidates gained from their pledge to kill it. [Daily Beast]

Conservatives committed to fighting ObamaCare to the end, however, say there's still a path to victory. Erick Erickson at RedState says more Americans than ever want the law repealed.

Sadly, some D.C. politicians have less enthusiasm than a wet rag, and would rather have futile discussions about the political implications of fighting to stop Obamacare. The American people deserve better from their public servants. [RedState]

If there is a window, it's about to close. ObamaCare's insurance exchanges are scheduled to make their debut in two months. As Greg Sargent at The Washington Post writes:

[K]eep an eye on how this defund Obamacare push plays. If it’s mostly a fizzle, it will confirm again that dissatisfaction with the law does not necessarily translate into support for doing away with it entirely, let alone replacing it with nothing. [The Washington Post]