US President Donald Trump has unveiled a $4.1 trillion budget for 2018 that will cut deeply into programs for the poor, from health care and food stamps to student loans and disability payments, laying out an austere vision for reordering the nation’s priorities.

The document, grandly titled “A New Foundation for American Greatness”, encapsulates much of the “America First” message that powered Mr Trump’s campaign.

It calls for an increase in military spending of 10 percent, spending more than $2.6 billion for border security — including $1.6 billion to begin work on a wall on the border with Mexico — as well as huge tax reductions and an improbable promise of 3 per cent economic growth.

The wildly optimistic projections balance Mr Trump’s budget, at least on paper, even though the proposal makes no changes to Social Security’s retirement program or Medicare, the two largest drivers of the nation’s debt.

To compensate, the package contains deep cuts in entitlement programs that would hit hardest many of the economically strained voters whose backing propelled the president into office.

Over the next decade, it calls for slashing more than $800 billion from Medicaid, the federal health program for the poor, while slicing $192 billion from nutritional assistance and $272 billion over all from welfare programs.

And domestic programs outside of military and homeland security whose budgets are determined annually by Congress would also take a hit, their funding falling by $57 billion, or 10.6 percent.

It would also cut by more than $72 billion the disability benefits upon which millions of Americans rely.

Student loan programs that subsidise college educations for the poor and those who take jobs in government or nonprofit organisations would be eliminated.

Mr Trump’s advisers portrayed the steep reductions as necessary to balance the nation’s budget while sparing taxpayers from shouldering the burden of programs that do not work well.

“This is, I think, the first time in a long time that an administration has written a budget through the eyes of the people who are actually paying the taxes,” said Mick Mulvaney, Mr Trump’s budget director.

“We’re not going to measure our success by how much money we spend, but by how many people we actually help,” Mr Mulvaney said as he outlined the proposal at the White House on Monday before its formal presentation on Tuesday to Congress.

Among its innovations: Mr Trump proposes saving $40 billion over a decade by barring undocumented immigrants from collecting the child care tax credit or the earned-income tax credit, a subsidy for low and middle-income families, particularly those with children.

He has also requested $19 billion for a new program, spearheaded by his daughter and senior adviser Ivanka Trump, to provide six weeks of paid leave to new parents.

The release of the document, an annual ritual in Washington that usually constitutes a marquee event for a newly inaugurated president working to promote his vision, unfolded under unusual circumstances.

Mr Trump is out of the country for his first foreign trip and his administration is enduring a near-daily drumbeat of revelations about the investigation into his campaign’s possible links with Russia.

The president’s absence, which his aides dismissed as a mere coincidence of the calendar, seemed to highlight the haphazard way in which his White House has approached its dealings with Congress.

It is just as much a sign of Mr Trump’s lack of enthusiasm for the policy detail and message discipline that is required to marshal support to enact politically challenging changes.

“If the president is distancing himself from the budget, why on earth would Republicans rally around tough choices that would have to be made?” said Robert L. Bixby, the executive director of the Concord Coalition, a nonpartisan organisation that promotes deficit reduction.

“If you want to make the political case for the budget — and the budget is ultimately a political document — you really need the president to do it. So, it does seem bizarre that the president is out of the country.”

While past presidents have often launched a road show with stops around the country to promote the components of their inaugural budgets, Mr Trump is spending the rest of the week overseas, leaving his staff to explain his plan while Republicans craft their own response.

Republicans balked at Mr Trump’s demand for money for his wall on the Mexican border in negotiations over a spending package enacted last month.

Many were deeply conflicted over voting for a health care overhaul measure that included the Medicaid cuts contained in the budget to be presented on Tuesday.

Now the president is proposing still deeper reductions to the federal health program for the poor, as well as drastically scaling back a broad array of social safety net programs that are certain to be unpopular with lawmakers.

To balance the books, Mr Trump’s budget relies on growth he argues will be generated from an as-yet-unformed tax cut.

Binyamin Appelbaum and Thomas Kaplan contributed reporting.