As I noted Tuesday in my column, it’s silly to claim “foreign aid” cuts can significantly offset a proposed $54 billion increase in defense spending. So why would the White House bother to suggest this?

Because most Americans — especially Republicans and Trump voters — vastly overestimate what the United States spends on foreign aid.

This truism was confirmed once again by a new Morning Consult/Politico poll of 2,000 registered voters. Respondents were asked whether various programs were big contributors to government debt. A whopping 46 percent said foreign aid contributes “a great deal” to government debt, whereas only 18 percent said the same about Medicare.

In fact, of all the programs included in this survey, “foreign aid” garnered the highest share of responses calling it a major contributor to federal debt.

For context, the United States plans to spend $36.5 billion this fiscal year on foreign assistance, compared with about $592 billion on Medicare (that’s net of premiums and other offsetting receipts).

Note also that a third of respondents believe Obamacare contributes “a great deal” to the federal debt, even though the Congressional Budget Office and Joint Committee on Taxation have found that on net the law reduces deficits.

Unsurprisingly, perceptions of the biggest drivers of debt are skewed by political ideology and partisan affiliation. For example, 63 percent of those who say they voted for Donald Trump in the 2016 election believe foreign aid contributes a great deal to national debt; just 33 percent of Clinton voters agree. (The shares for self-identified Republicans and Democrats are 57 percent and 34 percent, respectively.)

Another reason that Trump may need to pretend that “foreign aid” cuts will cover the cost of defense spending hikes? Even his own voters aren’t terribly keen on scaling back domestic programs.

Here are responses, broken down by party, to a question about what should happen to Medicaid spending:

Among Republicans, 56 percent think Medicaid spending should either stay the same or increase. Perhaps someone should inform Paul Ryan.

On other programs, majorities of Republicans also believe spending should stay the same or rise. For Medicare, 68 percent of Republicans say this; and for Social Security, the share is 73 percent.