President Trump (Shawn Thew/European Pressphoto Agency/EFE/REX/Shutterstock )

It’s often hard to tell when President Trump is making a policy argument in bad faith or if he simply misunderstands the issue. This is partly because his path into the American political debate was through the back door of spurious allegations and untrue news reports. It’s also because he’s been ostentatiously indifferent to policy details, and so much of the nuance of issues he’s asked to weigh in on are probably new to him.

In that context, this comment from Trump reported by Forbes on Tuesday is understandable. He explains to his interviewer why he thinks the government should slash foreign aid: “For me, it’s America first. We’ve been doing that so long that we owe $20 trillion, okay?”

To a layperson, that makes sense: We’re deep in debt; why would we give money to another country?

But a president should know better — particularly one who’s advocating a reform to the tax system that experts estimate will boost the debt far more than we spend on foreign aid.

Let’s walk through this. It’s true that the country is about $20 trillion in debt. As a percentage of the gross domestic product, we now owe more than our economy generates in a year.

That’s a function of annual spending exceeding the amount the government takes in. This is the annual budget deficit — which, for a few years in the booming 1990s, was actually a surplus. The deficit spiked during the Great Recession as the government increased spending on programs to support those affected by the collapsing economy and as tax revenue sank.

So this is Trump’s apparent point: Because we have this deficit, we can’t spend money each year on programs meant to aid foreign countries.

Setting aside the reason we spend that money — and there are many good reasons we do — let’s look at how big of a dent that spending puts in our budget. Here, from the White House Office of Management and Budget, is how much we’ve spent each year on international affairs since 1966.

It’s gone up, and is in the billions of dollars, both of which appear to support Trump’s point. But these aren’t adjusted figures, meaning that part of that rise is because of inflation. Moreover, on the scale of all federal spending, this amount isn’t much more than a blip.

The dark green section of the graph below is spending on international affairs.

Cut that section entirely, and the graph looks like this.

The difference is . . . subtle.

Trump and others might argue that you can’t cut the deficit without cutting spending somewhere, which is true — unless you add revenue. But Trump’s administration wants to slice revenue by cutting taxes for corporations and high-income earners. The net effect of his proposal will be a deficit increase of trillions of dollars over the next decade — $2 trillion by one estimate, $5 trillion by another. A $2 trillion increase is $200 billion a year, or six times what the Office of Management and Budget expects we’ll be spending on international assistance by 2022.

The head of that office, budget director Mick Mulvaney, recently disagreed with the president on one point by arguing that increased deficits were good because they would spur economic growth — a claim that is both disputed and a sharp break from Mulvaney’s past comments on the subject.

Trump’s attitude toward this policy, as with many others, is one of both having and eating his cake. He spent the 2016 campaign bashing President Barack Obama for increasing the federal deficit, but, as president, he endorses policies that would increase it further. Then when he wants to argue that we can’t afford to spend money on something he doesn’t like, the argument against boosting the deficit reappears — even though, in the same article, Trump explains why he wants to cut corporate taxes in a way that would make the deficit go up.

At the very least, we can’t say that these inconsistencies weren’t predictable based on what we knew about Trump before  his inauguration.