President Biden unveiled his $6.8 trillion budget proposal last week, and it drew the usual jaded reactions: a work of fiction. A party platform with price tags. And of course dead on arrival.

All true. But from Biden’s point of view, the budget rollout was a resounding success that served two purposes.

It put the president where he wants to be as he prepares for an anticipated re-election campaign, with one foot in the center of his party and one in the progressive left.

Biden pledged to centrists to cut future deficits by nearly $3 trillion and prop up Medicare’s deteriorating finances.

But he also asked for more money for childcare, elderly care and the fight against climate change, saying he would pay for the whole package by raising taxes on businesses and the wealthy.

In a campaign-style speech at a union building in Pennsylvania, he said his budget was to give working class people a fighting chance. Expect to hear more of that as he tries to win over those voters next year.

More importantly, the budget was Biden’s opening bid in a battle over federal spending that will likely consume the rest of the year.

The president knows that the Republican-led House of Representatives will not approve the social programs he has proposed or the tax increases that must be paid for them.

Besides campaign positioning, his real goal was to push House Republicans into serious negotiations and a vote to raise the debt ceiling, which limits government borrowing.

Republicans have said they won’t raise it unless they get sweeping cuts in exchange for an ultimatum that threatens to lead to a catastrophic government failure to pay its bills. But they haven’t yet come up with a comprehensive list of the cuts they want; there is no official GOP budget proposal.

They’ve largely reused traditional conservative demands for cuts they see as wasteful, plus one innovative wrinkle: They’ve pledged to cut the budget by eliminating wake-up spending.

And what, you may ask, is that? The definition is not clear.

Judging by the examples provided by the Republicans, the wake-up spending seems to encompass everything conservative voters dislike: racial equality efforts, especially in the armed forces; programs aimed at helping LGBTQ people; and anything to do with climate change.

Plus a hiking trail in the Atlanta suburbs. A $3.6 million federal grant to extend the Michelle Obama Trail is on the House Budget Committees hit list of awakened waste. If the DeKalb County Board of Commissioners had named the trail to Rosalynn Carter, it might not be in so much trouble.

But cutting every penny of so-called waking spending, no matter how broadly the term is defined, won’t eliminate the shortfall.

The waking trash list was put together by House Budget Committee Chair Jodey Arrington (R-Texas), who has offered the closest Republicans can come to a plan.

Arrington has proposed cutting domestic spending by $150 billion next year. That sounds like a lot, but it would reduce the federal deficit by only about 9%.

Which brings us to the House Republicans’ real problem: they’ve gotten themselves into a fiscal trap, thanks in large part to former President Trump.

For decades, conservatives have proposed balancing the budget in part by cutting future Social Security and health care spending.

But Trump abandoned that doctrine, and other Republicans, including House Speaker Kevin McCarthy of Bakersfield, voted in line, even as tax experts from both parties acknowledge the programs are headed for financial trouble.

So while Republicans want cuts, they’ve ruled out taking them out of the biggest programs: Social Security, health care, and defense.

To balance the budget in 10 years, as they say they want, they would have to cut nearly every other part of the government by an unrealistic 85%, according to the nonpartisan Committee for a Responsible Federal Budget.

Biden has also taken Social Security and health care off the table, but he’s built himself an escape hatch: He wants to tax companies and people who make more than $400,000 a year. That would allow him to put money into Medicare and reduce the national debt.

Republicans have never vowed to raise taxes, so they must find another solution to the math problem. They don’t.

Therefore, the danger of a fiscal crisis, not just a government shutdown, but also a catastrophic default on the federal debt seems greater this year than ever before.

The way to avert such a crisis is to start serious negotiations. Biden’s budget proposal has put the ball in McCarthy’s court. Where’s his plan?