But a significant number of Republicans can't get behind Trump's budget, some for the same reason. While they may appreciate the tax cuts and billions in extra military spending, a number of Republicans fear that Trump's budget goes too far in pulling the rug out from under people in their districts and states — especially for programs where their potential opponents can make the easy political case that they were heartlessly cut.

To wit:

On cuts to children's health-care programs, which the White House wants to cut by 29 percent next year: “There will be some concerns if we go too deep in some of these areas,” the chair of the conservative Republican Study Committee, Rep. Mark Walker (R-N.C.), told reporters Monday.

On cuts to Meals on Wheels: “I’ve delivered meals to a lot of people that perhaps it’s their only hot meal of the day,” Rep. Mark Meadows (R-N.C.), chairman of the hard-line conservative House Freedom Caucus, told reporters.

(If there's one group of lawmakers in Congress who should be applauding Trump's budget, it's this group Meadows chairs.)

On an economic commission to help people in Appalachia get jobs: “We are not going to allow any cuts to the Appalachian Regional Commission,” Senate Majority Leader Mitch McConnell (R-Ky.) told people back home in Kentucky this year. “It is very important to eastern Kentucky. It has been for a number of years. That’s not going to happen.”

On the fact that Trump's budget is a historic slashing of pretty much all domestic programs* “I’m deeply concerned about the severity of the domestic cuts,” Rep. Hal Rogers (R-Ky.), who sits on the powerful House Appropriations Committee, told Politico on Friday.

*Except for Social Security or health benefits for Medicare, which happen to be two of the most expensive parts of the federal budget and the two programs Trump told his team they could not touch, notes The Post's Damian Paletta and Robert Costa.

Trump's budget was never really intended to be written straight into law. Presidents' budgets never really are. And as Roll Call's Niels Lesniewski points out, President Barack Obama's budget was also really unpopular in Congress. Congress is the one that sets spending levels, and it's almost as if lawmakers of both parties resent being told by the White House what to do.

But that doesn't mean Trump's budget just dissolves into thin air after today. Democrats will absolutely use it as a marker for potentially vulnerable Republicans in Congress: Trump wants to cut health care for poor children/meals for poor families/art and science funding. Do you?

(A Republican candidate's answer to that largely depends on the political make up of their constituents: A 2016 American National Election Studies survey found that Republicans are 45 points more supportive of cutting welfare than the rest of the nation.)

On the other side of the political spectrum, Trump's budget could be used by Republicans' primary opponents as a marker of political purity: I stand with Trump on cutting hard-working taxpayers' bills and boosting military spending. Why don't you?

Even portions of the budget where Trump and House Republicans generally agree could be a political landmine for the party.

Trump wants to cut the federal help for Medicaid by $800 billion over the next decade, putting states on the hook for the health-care program for the poor that Obamacare expanded to millions of people.

Cutting back Medicaid = cutting back Obamacare. But Medicaid is also a program that Americans largely value: A March Quinnipiac poll found 74 percent of voters oppose cutting Medicaid.

To some degree, all presidents' budgets are political headaches for that president's party. But Trump's budget is notable for just how much of a no-win situation it puts Republicans in -- moderates and conservatives alike.

His decision to snip a giant hole in the social safety net just made it that much more difficult on Republicans to stand by him on one of the most basic jobs of the federal government: to fund itself.