Fiscal restraint has long been part of the Republican Party's brand, but GOP lawmakers have made little progress on reducing the amount of money the federal government spends. And frankly, they're sick of it.

That's the impetus for what has become a serious push by rank-and-file House Republicans to use the budget reconciliation process to enact mandatory spending cuts.

Various targets have been thrown around the GOP conference, but Budget Committee Republicans have agreed to write their fiscal blueprint with instructions for authorizing committees to collectively find $150 billion in mandatory savings over 10 years.

"There are a number of us on the committee that don't feel comfortable with moving a budget that doesn't in any way address the issue of entitlements," South Carolina Republican Mark Sanford said. The Freedom Caucus member said he feels a $150 billion target is "light" but that it's meant to serve as a compromise number.

House Budget Chairwoman Diane Black declined to confirm the $150 billion target but emphasized the need to reduce mandatory spending. "When you're $20 trillion in debt, you have to talk about the mandatory side because it's really where the spending is," she said.

The push for using reconciliation to get to mandatory savings has broad support among budget writers and members of the House Freedom Caucus and the Republican Study Committee, two conservative caucuses. The disagreement has been on the appropriate amount to write into the reconciliation instructions, with leadership concerned about setting too ambitious of a target.

"If it's more on mandatory (than $150 billion), that doesn't bother me at all," said Oklahoma Rep. Tom Cole, a member of both the Budget and Appropriations committees. "I mean, that's where we need to be focusing attention. I think our leadership is just very cautious. They don't want to overdo it ... set a target that is too wide or we can't reach."

For many Freedom Caucus members, $150 billion is not enough, but the hard-line conservatives have yet to coalesce around their own target. Ohio Rep. Jim Jordan floated $400 billion, while Virginia Rep. Dave Brat has said $300 billion or more. North Carolina Rep. Mark Meadows, the caucus chairman, said $300 billion appears to be the floor for the group but the key is for all authorizing committees to contribute to the deficit reduction.

"To date, the $150 billion does not include all authorizing committees," Meadows said, adding, "There are not 218 votes on the budget today."

Rep. Mark Walker of North Carolina, chairman of the Republican Study Committee, said his group also wants to see if they can do better than the $150 billion over 10 years. But the committee intends to reach an agreement on a target that Black and her panel can support. "We felt like there were a few more committees that need to ante up a little bit," Walker said. "Several of them were making some sacrifices."

While neither Meadows nor Walker mentioned specific panels, sources have pointed to the Agriculture Committee as being resistant to significant cuts. Agriculture Chairman K. Michael Conaway of Texas has declined to comment on specifics until the Budget Committee formally announces a target, but said Agriculture members will work with the panel on a budget "that accommodates what they're trying to do, as well as allows us to write a farm bill in 2018."

The Budget Committee is planning to mark up the fiscal 2018 budget resolution next week, according to Sanford and Cole. A GOP aide cautioned that while the committee would like to mark up the resolution as soon as possible, nothing is official yet in terms of timing.

In addition to the mandatory savings target, the committee's budget resolution would raise defense spending to $621.5 billion, which is $72.5 billion above the sequester cap, and cut nondefense spending to $511 billion, which is $5 billion below the sequester cap. The defense number is halfway between the $603 billion President Donald Trump requested and the $640 billion pushed by the House Armed Services Committee.

The committee's agreement has yet to be vetted by the full House Republican Conference, which met Wednesday to discuss the budget and appropriations process and is scheduled to continue the discussion Friday morning. It's unlikely the markup would be formally noticed until after Friday's meeting.

Wednesday's discussion largely sidestepped the debate on fiscal 2018 spending numbers and the 10-year mandatory savings target. Instead, House Republicans spent most of their meeting discussing how best to move appropriations bills across the floor this summer.

The options, according to multiple members present, included moving all 12 appropriations bills individually in committee and as many as possible on the floor, moving a national security-related package first or a security-plus package that would include energy and water and then trying to tackle the remaining measures, or simply starting with a 12-bill omnibus.

"We haven't decided exactly how we're going to go about our appropriations process in this first year, but we're going to move together on consensus," Speaker Paul D. Ryan told reporters after the meeting, noting that no final decisions had been made on the budget resolution either.

With a little more than seven legislative weeks before the end of the fiscal year on Sept. 30, the indecision has fueled some discontent in the conference. The Budget Committee members' plan to move forward with a markup without the conference's support for the budget plan reflects an interest in moving the process along.

"We need to get it out," Cole said. "And then if leadership needs to negotiate above that, they can do that. If we've got something we can move, we need to move soon. We can't solve the whole conference's problem inside the Budget Committee."

Still, Cole predicted the committee's compromise would attract the 218 Republican votes needed to pass the House.

"The mandatory helps a lot with people that are concerned about spending levels," he said. "And obviously, we need this vehicle for tax reform, so that's made everybody I think willing to come to the table a little bit more."

The plan to use budget reconciliation to advance a tax overhaul is more widely supported in the conference than the idea of adding mandatory savings to the mix.

Ways and Means Chairman Kevin Brady of Texas has expressed concerns about making a tax rewrite more complicated, and other members also worry that a spending cut target may inadvertently derail that effort.

"We all want to reduce the deficit, but we can't do everything on the same bill," said Florida Rep. Mario Diaz-Balart, also a member of both the Budget and Appropriations panels. "I want to make sure that whatever we do in reconciliation, whatever that number is, doesn't put in jeopardy the bill, the reconciliation bill, and then kills our shot at tax reform, which I think we have one shot at doing."

Diaz-Balart said he doesn't know whether a $150 billion spending target would thwart a tax overhaul or what the "magic number" is that would. "I just want to make sure that we don't put it in jeopardy," he said.