Earlier this morning, I Tweeted, “If the arguments in the coming years are between spending freezes and spending cuts, then we’ve already won.”

I’m getting a lot of pushback on it, with quite a few folks pointing to all the exceptions in Obama’s spending freeze.

My argument is not “hooray Obama,” and in fact it doesn’t have much to do with Obama’s specific proposal. My argument is that we’ve gotten a man who campaigned on expanding government to concede that his vision is not affordable. This is an enormous opportunity for those who want to see a smaller, more focused government.

For starters, any Democrat who opposes the spending freeze can now be justifiably painted as reckless, out of control, unserious about budget matters, and a threat to the nation’s long-term economic future. “Even President Obama says we have to freeze spending now. Why is Congressman So-and-so calling for even more spending that we can’t afford?” There is enormous potential to drive a deep wedge between Obama and a large part of the Democratic caucus.

Second, by making this proposal, Obama is conceding a large portion of the terms of the debate. For all extents and purposes, spending increases are now off the table. Will Obama probably switch back and propose more spending in coming years? Of course. But now the GOP can point to Obama’s own proposals and own words, not just as a candidate – because we know all of those statements come with an expiration date — but the centerpiece of his first State of the Union.

Mary Katharine Ham is of a similar mind, noting this promise is like Obama’s promise to have all health-care legislation negotiations on C-SPAN. If he keeps the promise, it opens the door for good reforms; if he breaks his promise, it’s another fantastic illustration that he’s full of . . . it.

UPDATE: For what it’s worth, Paul Krugman seems to agree:

Obama has embraced and validated the Republican world-view – and more specifically, he has embraced the policy ideas of the man he defeated in 2008. A correspondent writes, “I feel like an idiot for supporting this guy.”