Bipartisan defense legislation from three congressional committees identifies a perfect example of this gap. The Air Force must buy 72 fighters a year to meet its fighter-squadron target. Yet as one committee notes, “the resources to initiate and sustain such growth simply do not exist within the fiscal year 2020 budget request or [five-year spending] program, nor does the Air Force’s five-year plan for fighter procurement achieve 72 new aircraft within any year.” Multiply this contradiction across the services and their myriad personnel and weapons needs, and the overall defense budget shortfall jumps out.

Mr. Trump supports each of these goals, plus additional investment in missile defense and modernization of the country’s nuclear forces. Why doesn’t his defense budget reflect this? This incongruence between what the Pentagon officially asked for and its real needs stems from the White House itself. The budget request—$733 billion in 2020 and flat spending thereafter—was always an arbitrary set of numbers. No one at the Defense Department can explain how a $733 billion budget actually meets the requirements of the National Defense Strategy. In the absence of a confirmed defense secretary, the Pentagon did not push back against White House budget officials who have never supported the security strategy with sufficient resources.

How much would it cost to close this strategy–budget gap? Former Defense Secretary Jim Mattis and Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, repeatedly testified that matching budget to strategy required 3% to 5% annual real growth. Over the next two years, that totals $40 billion to $100 billion above the levels in the budget agreement that Speaker Nancy Pelosi and Treasury Secretary Steven Mnuchin recently reached. Over five years, that equates to around $550 billion in additional funding, exactly the amount of buying power the Pentagon lost under the Budget Control Act.