A president with business acumen should understand that throwing more money at an already over-budgeted asset isn’t wise.

Yet President Trump recently unveiled a federal budget blueprint that seeks “one of the largest increases in national defense spending in American history.”

The fiscal plan, when read with an understanding of what other countries spend on their militaries, fails to make a convincing case for increasing what’s an already massive expense - in our case, nearly $600 billion a year.

China spends about $150 billion a year, but our contentions with China are mainly in the economic realm. Russia, unlikely to send its military far from home, spends $60 billion a year and has been cutting back. North Korea, for all its missile-rattling, is small potatoes.

Trump’s budget justifies the spending hike by describing the military as being saddled with “aging ships, planes, and other vehicles” in need of replacement. But the document avoids the realities of how much such materiel cost.

Earlier this month, Trump assembled a Navy audience aboard the new USS Gerald R. Ford, a mammoth aircraft carrier that has given the term “cost overrun” new meaning. Price tag: $13 billion.

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Standing on its deck, he told the cheering sailors: “We’re going to soon have more coming.”

He did not mention that war games have shown gigantic aircraft carriers to be highly susceptible to today’s sophisticated anti-ship weapons or that we rely on such ships far more heavily than any other country.

And while Trump has done his share to pressure military contractors to keep their costs under control, the real question is whether such firms should be building these behemoths in the first place.

The budget’s stated goal of deterring war cannot be accomplished without strong diplomacy, yet the plan virtually guts the State Department, whose new chief, Rex Tillerson, seems content overseeing the drastic downsizing.

Trump is enamored of nuclear weapons but has not explained what a modernized nuclear force would look like or what purpose it would serve.

We are well beyond the Cold War strategy of mutually assured destruction, premised on the hope that neither we nor the Soviet Union would strike first.

Trump’s desired spending increase could perhaps be justified as a Depression-era-like measure to create jobs. But instead of spending more on a well-equipped military, we should direct those dollars toward another signature Trump aim: salvaging our crumbling infrastructure at home.

The budget explains that the increase in military spending will be balanced by cuts in other programs, many of them domestic.

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Nancy Pelosi, who leads the Democrats in the House of Representatives, says that the projected boost in military spending would cause “far-reaching and long-lasting damage to our ability to meet the needs of the American people.”

Trump was pressured by critics to stop being a businessman when he took the oath of office. Maybe those critics were wrong.

Maybe he needs to put his business hat back on.

John B. Quigley is a distinguished professor of law at the Ohio State University. He is the author of 11 books on various aspects of international law.T