(CNN) House Democrats on Tuesday zeroed in on "malicious" proposed cuts to health care and other social programs, reviving their winning midterm message in a first attack on President Donald Trump's proposed $4.7 trillion fiscal 2020 budget proposal .

Cuts by the Trump administration to programs like Medicare and Social Security, student lending and nutritional assistance for low income families drew attention from Democrats at a House Budget Committee hearing on the White House proposal released Monday.

"These cuts in the Trump budget aren't a tightening of the belt or a trimming of the fat, or even a serious attempt at reining in spending," said Kentucky Democratic Rep. John Yarmuth, the chairman of the House Budget Committee. "They are extreme to a level that is malicious -- a level that is intended to do harm."

The Trump administration included a 5% boost in defense spending in its third budget, the largest in history -- along with request for $8.6 billion to build a wall along the Mexico border. That's offset with a total of $1.9 trillion in cost savings from mandatory safety net programs, like Medicare, breaking a repeated promise by the President not to cut those services.

His budget reduces spending in Medicare, a federal health program for the elderly, by $845 billion over 10 years, from current law.

On Tuesday, former Vice President Joe Biden, who is eyeing a possible 2020 presidential bid, sharply criticized the Trump administration's plan to cut health care, arguing the proposal hurts middle-class families in order to help pay for a tax cut scripted for the country's super wealthy.

"Something they gave, millionaires and billionaires excessive tax breaks, and who are they asking to pay for it?" said Biden, speaking at firefighters' conference in Washington, DC. "Middle class families like you, and the neighborhood I grew up in. Trading Medicare and Medicaid for tax breaks? How is that going to help the people in this room or most of the people you live with."

At the hearing, Trump's acting budget director Russell Vought disputed press reports that the White House is planning to cut $845 billion from Medicare, calling the numbers "inaccurate."

Instead, he said, there would continue to be a rise in Medicare spending every year, but that the administration has identified cost reductions of $517 billion in programs like lowering drug prices. The administration's figure includes the shifting of two programs out of Medicare's budget, as well as some indirect cost savings.

That defense prompted Democratic Rep. Lloyd Doggett of Texas, chairman of the health subcommittee for the House Ways and Means Committee, to press Vought at the hearing on whether the Trump administration would endorse a proposal to cut drug prices that would also include direct negotiations with Medicare on prescription drugs.

"President Trump has not put forth those policies in this. ... He hasn't proposed what he advocated for as a candidate?" Doggett pressed, referring to the President's campaign promises. "Medicare prescription drug negotiation is not one of them. Are you against it?"

Vought said the administration had not proposed such a plan as of yet.

"We want to continue to have a conversation with Congress -- of all the proposals you have put forward," he said.

To increase savings in the budget, the White House proposal also asks Congress to craft legislation to repeal former President Barack Obama's signature health care law, the Affordable Care Act, and expand the use of accounts that let individuals pay for health care with pretax dollars. Previous attempts to undo the Affordable Care Act failed when Republicans held both congressional chambers and are non-starters under a Democratic-controlled House.

Democratic lawmakers pressed Vought on why the administration focused cuts on discretionary nondefense spending rather than mandatory spending programs, despite the fact they are a larger contributor to the country's widening deficit.

"I would agree it is one of the largest drivers -- I might even agree that it is the biggest -- but when I say that I'm trying to avoid conceding the fact that we have not dealt with our discretionary problem and that in many ways is how you start as a country getting a hold of your fiscal challenges by identifying the waste and abuse and the inefficiencies in the votes that members take every single year," said Vought. "This is the process that is not on autopilot."

The White House predicts rising deficits beyond the standard 10-year time horizon for federal budgeting, but claims the budget will balance in 15 years, assuming optimistic growth.

The President's budget anticipates, however, that the country's debt will grow to $31 trillion over the next decade.

The White House is forecasting that the economy will grow at an average of 3% each year over the next decade, including 3.2% in 2019. While such forecasts are difficult to predict, the White House figure is at odds with projections made by the International Monetary Fund, which anticipates US growth will decline to 2.5% this year and soften further in 2020 as the fiscal stimulus of the Republican-backed 2017 tax cuts fades.

When asked if the administration had crunched numbers for the possibility of GDP falling short of expectations, something closer to 2%, Vought said officials in the budget office "haven't run alternative scenarios," adding, "We're going to be vindicated."

Yarmuth told reporters at a pen-and-pad on Monday that Democrats plan to rely on baseline estimates by the Congressional Budget Office, which currently forecasts 2.3% for 2019, in drawing up a counteroffer. "We think that's much more realistic," he said.