House Republicans are vowing to put Don Quixote to shame by tilting at a huge windmill: slashing federal spending by at least $130 billion without cutting defense.

It’s a proposition that’s severely unlikely on its face, before factoring in a Democratic Senate and White House that would never accept such cuts. Even the GOP’s fallback plan for avoiding a shutdown later this year — passing a short-term funding patch that would trigger reductions as an incentive for lawmakers to finish comprehensive spending bills — is inconceivable this term.

In other words, the government funding process appears over before it really even started, as top House Democratic appropriator Rep. Rosa DeLauro of Connecticut quipped earlier this week.

And that funding work is one of the few items Congress has to accomplish this year as part of basic governing. While lawmakers had always expected appropriations would be a struggle this term, the spending concessions negotiated by Speaker Kevin McCarthy and his conservative foes have raised members’ blood pressure. Those House GOP demands could set the stage for a government shutdown, unless conservatives relent or enough moderate Democrats come to other Republicans’ rescue.

“I don’t think we’ve had a really good full-throated discussion and debate about what is politically doable,” said Rep. Steve Womack of Arkansas, a Republican appropriator.