Donald Trump is reaching for more power over government spending, and conservatives in Congress appear eager to cede their authority to him.

The $1.3 trillion US spending bill signed into law in March was a classic Congressional compromise: In exchange for enacting large defense spending increases desired by the Republican party and the White House, Democrats achieved major expansions of funding for domestic programs from health care to community grants.

Trump doesn’t like compromise, and complained about the bill even as he enacted it. He also expressed interest in a line-item veto—the ability for a president to reject not just an entire bill, but individual provisions within them. US courts have consistently held the line-item veto is unconstitutional because it robs Congress of its power of the purse.

Presidents who still want more say over spending often turn to another rarely-deployed power: Rescission. Enacted by the same 1974 law that created the Congressional Budget Office, rescission allows presidents to reject spending authority as long as Congress agrees, by a simple majority, within 45 days. This is what the White House and House Majority leader Kevin McCarthy are reportedly now contemplating, though the extent of the cuts and their targets remains unclear.

Such a move appeals to the politics of the House of Representatives, where a Republican majority controls the House and could likely unify around domestic discretionary cuts. Mark Meadows, a legislator who leads the ultra-conservative Freedom Caucus, praised the idea of retroactive spending cuts. Such cuts would likely mean little to long-term fiscal sustainability, since domestic spending remains a small chunk of total outlays compared to mandatory programs and defense spending.

In the Senate, enacting back-dated spending cuts on potentially popular programs is a far harder sell. Senate Republicans have a bare one-vote majority only with vice president Mike Pence’s tie-breaking vote, and several members face tough challenges from both primaries and Democratic opponents. Individual rescissions are rare because they undermine the credibility of deal-making lawmakers.

And revisiting this year’s spending authority, which expires in just six months, is not at the top of Senate majority leader Mitch McConnell’s schedule. Lawmakers are supposed to be prepping spending bills now for the fiscal year that begins Oct. 1, 2018. And the Senate needs to confirm replacements for departing members of Trump’s cabinet, including Secretary of Veterans Affairs Eric Shulkin, Secretary of State Rex Tillerson and CIA Director Mike Pompeo, who has been tapped to replace Tillerson.

Some Republicans will relish the chance to debate spending proposals during an election year, but most would likely prefer campaign season message legislation to paint them in a friendlier light—Nevada senator Dean Heller, perhaps the most vulnerable Republican, has been boasting about increases in spending passed in the law.

All that limits the prospects for a retroactive budget cut through rescission—but conventional political strategy tends to go out the window while Trump is in the Oval Office.