President Obama says he wants to save $400 billion in defense spending over twelve years by reevaluating military roles and missions. My last post discussed the problems with calling $400 billion “savings.” You can save that much by simply growing defense spending at inflation, rather than the faster pace assumed in the White House’s latest budget submission. And it’s doubtful that this White House’s foreign policy beliefs permit the strategic changes that even such modest spending restraint requires.

Here I expand on a point I made in passing in that post. It is futile to bank on future years’ savings. Futility increases with the time planned. One reason is that Congress gets a say. Another is that administrations cannot lock themselves into their own plans, let alone plan for future administrations. Budget plans change with political circumstance.

The graph below makes that point clear. It is from 2002 Congressional testimony by legendary defense analyst Chuck Spinney.* It compares actual defense spending with the five year defense plans (FYDPs) that the Pentagon must produce annually with its proposed budget.

The lines shooting off every which way show the difficulty of planning spending. Extending the lines to twelve years would increase the margin of error. This New York Times graphic makes a similar point about total deficit estimates.

The fault is not the Pentagon’s. As Aaron Wildavsky long ago explained, politics, particularly the democratic sort, is a competition of plans. Success depends on the power to implement plans, not their content. Implementing present plans requires a victory in today’s political fight. The future budget plans attached to this years’ tend to serve as weapons in that fight. They are, that is, as much sales literature as prediction. And even if they are honest, implementing future plans with today’s words, however official, is essentially impossible. The further into the future you plan, the more the political actors change, and the sillier plans become. If every plan in life is a tiny prayer, it’s especially true in politics.

*Spinney has a good essay discussing the failures of FYDPs and Quadrennial Defense Reviews in a brief new essay collection from the Center for Defense Information, The Pentagon Labyrinth: 10 Short Essays to Help You Through It. The book should be useful to new defense analysts. It gives the basics about the Pentagon, particularly its budget, in short, clear essays. The contributors are mostly from the grizzled defense reform crowd, whose heresies are badly needed in today’s defense politics. The book distils much of their long experience in cutting through the misinformation that surrounds defense policy.

My only complaint is that the essays tend to blame policy failures on the foolishness or self-interest of policy-makers rather the political incentives that make those predictable human behaviors destructive. To learn about the politics that cause these outcomes read Harvey Sapoksly, Thomas McNaugher, Warner Schilling and Arnold Kanter.