Washington (CNN) Once the party of fiscal discipline, Republicans are learning under President Donald Trump that spending money is much easier in Washington than cutting back.

Less than two months after their $1 trillion tax cut, the House will vote on a spending bill Thursday that raises budget caps by $300 billion in the next two years, increases the debt ceiling and offers up more than $80 billion in disaster relief for hurricane-ravaged Texas, Florida and Puerto Rico.

It's a scenario that would have been unimaginable just eight years ago, when Republicans routinely bludgeoned President Barack Obama's $787 billion economic stimulus package, held the line on debt ceiling increases and took back the House of Representatives on a tea-party-fueled message of fiscal austerity.

In the era of Trump, a real estate mogul and self-proclaimed "King of Debt," the Republican Party has eased into a cycle of big spending it once abhorred.

It's a symptom of both an evolving economic climate and the political realities that governing parties face. While the GOP controls all three branches of government, it still must depend on Democratic votes to overcome a Senate filibuster, and they wouldn't agree to spend more on the military without boosting domestic programs as well.

It also shows the White House's willingness to deal, despite the President raising the specter of a government shutdown just two days ago.

In the end, that meant more money for everyone.

A "Christmas tree on steroids," said conservative Rep. Dave Brat of Virginia, a critic of the deal.

"Adding to the deficit is a real concern, and that was voiced very loudly in our conference," said former House Appropriations Chairman Hal Rogers, R-Kentucky. "However, with a desperate need to add additional needs to defense and then the necessary Democrats' demand that we also increase non-defense domestic spending, it was apparent that we had to do that."

Thursday, Republicans are expected to be divided on the plan before them. If the bill passes it will be because enough Republicans and Democrats in the middle are willing to come together and swallow something both sides admit is less than optimal for them.

But after months of careering from one budget crisis to the next, lawmakers say it's time to put an end to the impasse.

Moderate Republicans, appropriators and defense hawks argue the deal is a good one that clears the legislative deck, keeps the government funded and gives the military much-needed financial certainty despite the fact that it increases spending in a major way. And it avoids future continuing resolutions, or CRs, those short-term spending bills detested by both parties.

"I've been yapping about this since April of last year, that we needed this bipartisan, bicameral deal. Now that we have it we need to support it," said Rep. Charlie Dent, a moderate Pennsylvania Republican. "It will get us off of this treadmill of CRs and out of these circular firing squad discussions, this hell that we've been going through over the CRs for months now."

Democrats aren't all happy about the deal either, especially in the House, where liberals wanted to address immigration as part of the agreement. Minority Leader Nancy Pelosi of California gave an eight-hour speech on the House floor -- a record -- decrying the lack of a resolution for the Deferred Action for Childhood Arrivals policy.

Getting things done may also help the Republicans next fall. Trump's approval ratings have ticked upward since he signed the tax cuts in December, and this deal can allow the White House and GOP leaders to tout the military spending and promote the idea they can get things done.

"The Budget Agreement today is so important for our great Military. It ends the dangerous sequester and gives Secretary Mattis what he needs to keep America Great," the President tweeted. "Republicans and Democrats must support our troops and support this Bill!"

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Conservatives not happy

Conservatives blasted the deal as little more than a blank check and an abandonment of the party's core principles.

"This is not what we were elected to do and you are going to see the vast, vast majority of Freedom Caucus members voting against it and a lot of other members as well," warned Rep. Jim Jordan, an Ohio Republican who's a leader in the conservative House Freedom Caucus.

Rep. Mark Meadows, a North Carolina Republican who's the Freedom Caucus' chairman, said he doesn't believe many caucus members will support the bill.

Even Sen. Bob Corker, a Republican from Tennessee who backs increased defense funding, said he thought the deal went too far.

"I'm discouraged," Corker said.

But defense hawks say the conservatives need to realize this is what governing looks like.

"They are always the problem children," Rep. Mike Rogers of Alabama lamented of the Freedom Caucus. "Some of them want attention and some of them are just knuckleheads, but this is the same exercise we go through every time. ... They have to have their tummies rubbed and have to have a lot of attention from folks like you, and they want the President to come over and hug on them a little bit, and some of them will eventually come around."

During a closed-door meeting Wednesday, New York Republican Rep. Peter King said House Speaker Paul Ryan acknowledged the GOP had made concessions, but told his colleagues it was the best deal he could get.

King sidestepped conservative blowback to the deal, saying, "look at the big picture: as long as there are 60 votes in the Senate I think this is very best deal we can get."

Tax plan must produce growth

Most Republicans say they can rationalize the increase in spending, arguing that the tax bill will generate economic growth they believe will more than cover the cost of their plan, a fact that remains to be seen and has been disputed by economists.

"It all comes down to one thing, economic growth. That tax plan has got to produce economic growth," said Rep. Dennis Ross, a Republican from Florida.

Others argue that the military needs of the moment outweigh any high-minded commitment to fiscal austerity.

"It's more than I like, obviously. But, the exigencies of the moment demand that," Hal Rogers said.