President Obama's 2015 budget proposal is as much a thought experiment as an actual budget plan: As with the proposals that were attached to his State of the Union address last night, it's not intended as a realistic fiscal blueprint, but as a positioning statement for his administration and his party, in 2015 and beyond.

As former vice presidential adviser Jared Bernstein told The Washington Post, the new budget is "setting up the 2016 debate in a way that only someone with his bully pulpit can do." Think of it as a fan-made teaser trailer for the next Democratic administration, not a plot for this one.

Republicans were certain to oppose most of the proposal before we knew what was in it. And sure enough, now that the details are public, the GOP doesn't particularly like what it sees. As Politico notes, various Republicans in Congress have called the budget "laughable," a "retread" that's "partisan, not practical." It's a "repeat of the same old top-down policies," said House Speaker John Boehner. House Ways and Means Committee Chairman Paul Ryan said it's "more of the same, more tax increases that kill investment and jobs, and policies which are hardly aspirational."

Republicans are obviously not working too hard on fresh material for their responses themselves, but they're also not wrong. The new administration budget isn't strictly a rehash, but it looks awfully familiar to anyone who's been following along—particularly in the way it emphasizes increases in spending. As Reason's Nick Gillespie noted earlier, Obama's budget is a wish-list for a federal spendathon. The budget proposes breaking caps imposed by the sequestration process on both defense and domestic spending. Obama wants to hike domestic spending by $37 billion over the sequestration limits, and expand defense spending by $38 billion.

Congress is ultimately in charge of the federal budget, so much of what Obama proposed is already dead in the water. But when it comes to increasing defense spending, the president may find common ground with Republican on Capitol Hill.

The dynamic here is completely straightforward. The military wants more money. Lots of Republicans want to give the military more money, entirely apart from whether the military needs it. And the Obama administration doesn't want restrictions on the handouts it can give to the defense industry.

The military has been fretting increasingly loudly over the spending caps it's been expected to hold to, and the White House has chimed in to help make the case. "This administration has been very clear, as have our military leaders, about the fact that sequestration is a bad policy," White House spokesperson Josh Earnest said last week, according to the Los Angeles Times.

Meanwhile, Republican defense hawks have used the Pentagon's pleas to continue making their never-ending case for more military spending. The reliably hawkish Sen. John McCain (R-Ariz.), for example, declared recently that "America's national defense can no longer be held hostage to domestic political disputes totally separated from the reality of the threats we face."

On the contrary, it's the military and its budgetary backers who aren't facing up to reality, which is that military spending is already pretty generous, and the Pentagon is blowing huge amounts of money on high-tech weapons initiatives of dubious value.

In addition to $51 billion in war funding that's already allocated, President Obama's budget requests $561 billion for defense spending, which includes the biggest baseline Pentagon budget ever. Sequestration caps for military were already loosened from initial levels in a budget deal made in 2013. And the Pentagon has managed to keep spending freely on boondoggles like the Joint Strike Fighter—a $400 billion futuristic fighter that has serious trouble with basic functionality, like flying—and a program to build new nuclear bombers and subs expected to cost about $350 billion. This is not a picture of a fighting force that is desperately starving for cash.

Breaking budget caps to spend even more on the Pentagon, then, doesn't seem like an idea with a whole lot of merit. But of all Obama's budgetary thought experiments, it's the one that's most likely to become reality.