Slashing funding for the IRS, the Coast Guard and legal aid for the poor would not move the needle on the United States' long-term debt problem.

Yet these and other domestic programs are exactly where President Trump focused his proposed budget cuts on Thursday.

This kind of spending -- called nondefense discretionary spending -- goes to everything from education programs to food stamps to foreign aid to technology grants to national parks and museums.

Agencies and divisions thought to be in line for big reductions include the Environmental Protection Agency, the State Department, the Coast Guard, the National Endowment for the Arts and the IRS.

The cuts have been touted by the White House as signs of Trump's push for fiscal prudence and his desire to root out waste and duplication.

But they're also intended to pay for his proposed $54 billion increase in defense and homeland security spending.

As it is, spending on nondefense discretionary programs is already historically low. As a share of the economy it's at its lowest level since 1998 and is well below where it was 50 years ago, according to data from the Congressional Budget Office.

Related: Lawyers fear Trump may kill legal aid

What's more, some of the programs on the president's expected hit list have already seen real cuts.

For instance, the Environmental Protection Agency now has less money in absolute terms than it did just a few years ago, according to the Bipartisan Policy Center.

The EPA, which Republicans often accuse of regulatory overreach, is operating with $2 billion less than it had in 2010.

And the IRS is now operating with about $900 million less than it got seven years ago.

The Bipartisan Policy Center also found that lawmakers have been spending less money compared to several years ago on education and health research and training, pollution control, job training, and community development.

Federal balancing act: An interactive budget simulation

For instance, funding for research and development -- which is the front line for future innovations that grow the economy -- is near its lowest level as a share of the economy in 50 years, down from its all-time high in 1964.

Meanwhile, within 20 years, CBO projects that entitlement spending plus interest -- which are the primary drivers of the country's long-term debt -- will suck up virtually every tax dollar coming into the federal government, up from 65% today.

Trump has often said he does not want to touch the biggest entitlement programs -- Medicare and Social Security.