By Chris Adams

Sequestration. OCO funding. Base funding – but not “base” like the place where troops are stationed.

For reporters covering military spending, the Pentagon budget is an often-bewildering document that comes with major zeros attached. It involves more than $700 billion in spending, the biggest pot of discretionary spending in the federal government and the third largest overall, following madatory Social Security and health care spending.

It’s also undergoing a fundamental shift, from a declared focus on fighting terrorism to one in which countering China and Russia is preeminent. Making sense of the Pentagon’s budget was the focus of a session with National Press Foundation Paul Miller fellows by Mackenzie Eaglen, a resident fellow at the American Enterprise Institute.

Eaglen (bio, Twitter) gave a detailed tutorial on how the budget process is supposed to work and how it actually does. “There are a lot of versions of the defense bill,” she said.

Eaglen discussed the different budgetary baselines used by the administration and Congress and what the differences among them mean. (She recommended reporters focus on the “050” budgetary line item.)

She also decribed the process by which OCO – “overseas contingency operations,” or war – funding is used for non-war purposes as a way to evade congressional spending caps. And she talked about sequestration, the process that could lead to arbitrary cuts in spending.

Eaglen also detailed the Pentagon’s different spending pots – from personnel, to procurement of weapons systems, to research and development, to the operations and maintenance fund that covers daily operating costs.