With the caveat that we haven’t seen the exact text of today’s presidential declaration of a national security emergency, there is credible reporting the Pentagon will be asked to cough up roughly $3.5 billion for a border wall. And the speculation is that these funds will come from the military construction portion of the Pentagon’s budget.

On the one hand this makes sense, in an Alice-falls-down-the-rabbit-hole kind of way. The Pentagon has a huge budget and stealing some of its construction funds to pay for construction of a border wall is an apples-to-apples/construction-to-construction trade off. On the other hand…good luck getting the Congress to acquiesce on this.

Military construction funds are so-called “five year money”. This means that money appropriated in any fiscal year is available for obligation for up to five years. This contrasts with operations and maintenance funds which must be spent in the year for which it was appropriated. Other pots of money have different rules. So, if you’re looking for a pot of money that goes back a few years, and where you may find some unobligated balances to sweep up, military construction makes a certain kind of sense.

That said, military construction funds are heavily controlled and very specifically appropriated for projects on certain military bases. This isn’t a case of appropriating a large pot of money for Army military construction, for instance. Instead, tables included in the appropriations act specifically call out the dollar figure, the name of the project, the military base, and the state. And that means that Members of Congress know exactly how much money the military services intend to spend in their state or Congressional District. For instance, the Fiscal Year 2019 appropriation for Military Construction includes $29 million for a “Multipurpose Range Complex” at Ft. Irwin, California. And that project has at least one House Member, two Senators, and the United States Army all with a vested interest in making sure that money isn’t spent on something else.

To put this in fiscal context, we’ve put together this handy chart to show that $3.5 billion is quite a bit of money when you’re talking about relatively scarce military construction dollars. In fact, it’s about 10 percent of all the money appropriated for that purpose in the last five years (remember, after five years these funds expire.)

If 10 percent of the money the Congress has dedicated to specific construction projects in the last five years hasn’t been spent, we would suggest there needs to be some increased oversight. But given the Congressional rice bowls that are about to be broken, the Appropriations and Armed Services Committees are probably way ahead of us.