Conservatives were jubilant just a month ago at the Conservative Political Action Conference, hailing President Trump as a conquering hero who would advance the cause of conservatism and potentially even redefine it. Kellyanne Conway, counselor to the president, declared that CPAC could practically be renamed "TPAC," dropping the "conservative" and switching it out for "Trump."

But a month later, many who have built their careers on conservative "purity" are on a collision course with a president who is beloved in their districts and who proved in his primary victory that the Republican Party's center of gravity may not be about doctrinaire conservatism after all. And the survival of the new healthcare reform bill in the short run may depend quite a bit on whether or not it becomes known as "Trumpcare."

Last week, House leaders rolled out long-promised legislation to "repeal and replace" Obamacare, the American Health Care Act, which focuses mostly on changing the taxation and spending portions of 2010's Affordable Care Act. In a great boost for House leaders, Trump put his support behind it, and the Sunday morning airwaves were full of executive branch leaders touting the legislation.

House Republicans have not had an assist from the executive in quite some time. In fact, seven out of ten House Republicans have never served with a Republican president before. The idea that one can pass a bill and have a plausible chance of it being signed into law is a whole new world for Republicans on the Hill. Furthermore, roughly two-thirds of them weren't in Congress when the Affordable Care Act was signed into law in the first place. (In contrast, about half of the Democratic caucus has been around since pre-Obama, and one in ten were elected before Bill Clinton was president.)

Being in the opposition makes messaging simple. Stopping bad things from happening, standing up to leadership, these are all easy sells in this climate. Arguing in favor of something? Much, much harder, as Republicans are learning.

All of which makes the president's role in championing the bill so important and makes him the biggest X factor in the whole debate. It would be the easiest thing in the world for Trump to come out and slam the bill, to lob angry tweets down Pennsylvania Avenue at congressional leaders, simultaneously criticizing them for failing to cover as many people and for failing to roll back all of Obamacare and start from scratch. (This may, ultimately, be how this story ends.)

This is why having the White House on their side right now — having the president's secretary of Health and Human Services serve as a major face of the bill, having the president play a big role in cajoling reluctant or recalcitrant conservatives, putting the president's own OMB director out in front to defend the bill's impact — is so valuable. When Trump is tweeting at Rand Paul instead of Paul Ryan, that's a good day for House leaders.

For all that's been written about Trump's poor approval ratings, the truth is that being around 45 percent approval isn't too bad compared with nearly every other political entity or person in the American political landscape right now.

And in many of the districts that House Republicans represent, Trump was elected by very wide margins. The House Freedom Caucus members, among the most vocally concerned about the bill from the right, come from districts where Trump won by an average of 25 points. It's one thing to say you're standing up to House Leadership in defense of conservative principles; it's quite another to look at your voters and say you're standing up to Trump.

There are some House Republicans who will be unmoved by a presidential push. Rep. Ileana Ros-Lehtinen of Florida has said she won't vote for the AHCA due to concerns about her own constituents losing coverage. In the Senate, some moderate Republicans are also threatening defection over similar concerns.

But Trump has the potential to scramble the political calculations for the most conservative and oppositional members of the Republican conference. For a long time, many of the organs of the conservative movement — groups such as FreedomWorks and Heritage Action, and their congressional champions in the Freedom Caucus — have relished standing up against leaders. It may seem easy to throw rocks at Speaker Ryan if you're in a deep-red district; it's a lot harder to speak out against Trump.

Over the long run, whether or not people support Republican healthcare policies will have everything to do with how those policies affect their wallets, their tax returns, their premiums, and the care they receive. But in the short run, the role Trump can play in shoring up support for this bill on the right cannot be underestimated. Far-right conservatives gambled on Trump. Now they have Trumpcare, and may have to grapple with what happens when "Trump" has replaced "conservative" in their movement.

Kristen Soltis Anderson is a columnist for The Washington Examiner and author of "The Selfie Vote."