– Budget Director Mick Mulvaney, who until months ago was embraced by conservatives for his relentless budget-slashing advocacy, returned to Capitol Hill on Wednesday as the White House's chief spending-cut champion — and found both Republicans and Democrats challenging him.

Mulvaney, a Tea Party favorite who until February represented South Carolina in the House of Representatives, got an earful not only from Democrats but also from fellow Republicans over the size of the reductions President Donald Trump proposed in his $4.1 trillion 2018 budget.

Republican Rep. Mark Sanford, a former South Carolina governor who warmly greeted Mulvaney as a fellow fiscal hawk, jumped on him for the budget's assumption of 3 percent annual economic growth.

"I have looked every which way to [see] how you might get there, and you can't get there," Sanford told Mulvaney. "The Bible says you can't build a house on a sandy foundation. What it does is perpetuate a myth that we can go out there and balance the budget without touching entitlements. It's not only a myth, it's frankly a lie."

Sanford went on to call the 3 percent projection a "Goldilocks economy, and I think that's a very difficult thing [on which] to base a budget."

"It assumes that the stars perfectly align with regard to economic drivers," Sanford added. "Can you guess the last time we had an unemployment rate of 4.8 percent, growth at 3 percent and inflation held at 2 percent? It's never happened."

Rep. Tom Cole, R-Okla., praised Mulvaney for presenting a plan that tries to balance the budget within 10 years — then criticized the same proposal for cutting the budgets of the National Institutes of Health and the Centers for Disease Control and Prevention.

Cole warned of a potential pox on the Trump White House: "I'll tell you, sometime in the president's term, you will have a pandemic. You will have a Zika, you will have an Ebola, and cutting the Center for Disease Control," he said, "I think, leaves you very vulnerable and the American people very vulnerable."

Mulvaney calmly responded that "despite what you may have read in the press, we wholeheartedly support research in this area."

The scolding Mulvaney received from fellow Republicans was mild, however, compared with the criticism of Trump's budget he received from Democrats.

Freshman Rep. Pramila Jayapal, D-Wash., began the barrage by telling Mulvaney that Trump's budget proposal is "shockingly extreme."

Rep. Barbara Lee, D-Calif., added that "rarely have I seen such a cruel and morally bankrupt budget."

"It dismantles our nation's basic living standards, which Americans have turned to for decades," she said. "This budget — and you know this — it will push millions of people into poverty and over the edge. This budget destroys people's lives."

Mulvaney defended the budget as moral.

"What about the standard of living for my grandchildren who aren't here yet? Who will end up inheriting $30 trillion in debt, $50 trillion in debt, $100 trillion?" he said. "We should be paying for it, because right now my unborn grandchildren are paying for it, and I think that is morally bankrupt."