Four months after Donald Trump won the presidency, Americans have gotten only the barest glimpses of what his budget will look like. So far, they offer a nightmarish view that betrays how little this White House seems to know about basic budgeting, let alone fiscal responsibility.

At some point, political rhetoric must give way to the hard reality of numbers. For Trump, that time is here. The plan he has proposed so far is a casino bet writ large: He would boost military spending, maintain Social Security and Medicare, embark on massive infrastructure rebuilding, and gamble that dramatic tax cuts for corporations and the middle-class would trigger explosive economic growth to pay for it all.

There is scant evidence for such a scenario. How about some realism? The areas he has pledged to protect or expand also are the three biggest drivers of federal spending. Social Security and Medicare alone account for 40 percent — a figure that will accelerate as the U.S. population ages.

Trump says he would get tough on other domestic spending. But the cuts identified so far appear designed to cause maximum pain for political opponents while producing minimal gains for the bottom line. Slashing funding for arts, humanities, public broadcasting and legal services won't make a dent in what is needed. On the other hand, the 25 percent cut to the Environmental Protection Agency being considered would do real damage to decades of work in that area. One target that should be of particular concern to Minnesotans: Funding for the Great Lakes Restoration Initiative, which protects the largest fresh surface water system in the world, would be nearly wiped out.

Decimating foreign aid, as Trump has proposed, would rob the State Department of its best leverage and create greater instability in the world. Secretary of Defense Jim Mattis put it best a few years ago, when he was head of the Pentagon's Central Command and told Congress: "If you don't fund the State Department fully, then I need to buy more ammunition."

Meanwhile, little has been said about one of the biggest cripplers in the federal budget — a national debt that stands at nearly $20 trillion. Interest on the debt alone tops $302 billion a year. Just to give some context to that staggering figure, the federal government now pays more in interest on the national debt than it spends on education, training, employment, social services, transportation, law enforcement, prisons, border security and civil courts.

That's not even the worst of it. One benefit of a sluggish recovery has been historically low interest rates. If the economy picks up, as Trump projects, interest rates will rise, which could send U.S. debt service soaring.

It's worth noting that President Barack Obama and Congress could never reach agreement on significant budget reform. The Star Tribune Editorial Board found much to like in two of this decade's most responsible deficit-reduction plans — Simpson-Bowles and Domenici-Rivlin — but they both suffered early political deaths despite significant bipartisan support.

Trump is about to bump up against an uncomfortable but immutable truth that those respected plans addressed: There is no way to produce a balanced budget that protects entitlement spending, increases defense and cuts taxes. The debt would only grow, further burdening future generations. Old budget hands like House Speaker Paul Ryan know that. But Ryan's solution is one many Americans will find unpalatable: a reordering of Social Security, Medicare and Medicaid that would hit seniors and the disabled hardest. That runs directly counter to the populist agenda that got Trump elected, one in which he specifically promised to protect those programs.

There is a clash coming between Trump's expansive, economic nationalism and a Republican Congress that has long been waiting to dramatically shrink government. If Trump wants any semblance of his vision to prevail, he'll have to create a real budget that deals in real numbers. The world's largest economy hangs in the balance.