What you see in his budgeting proposals, I think, is the liberal equivalent of the conservative attempt to "starve the beast." In both the Reagan and Bush eras, Republicans passed tax cuts and ran up large deficits while hoping that by starving the federal government of revenue they would curb its long-run growth. Obama's spending proposals would effectively reverse that dynamic — they would create new spending commitments and run up large deficits, in the hopes that the dollars poured into health care and education will create a new baseline for government's obligations, which in turn will create the political space for tax increases on the middle class. Like the starve-the-beast approach, the Obama strategy puts off the hard part till tomorrow: Give them tax cuts today, conservatives said, and they'll swallow spending cuts tomorrow; give them universal health care, universal pre-K, subsidies for green industry and all the rest of it today, liberals seem to be thinking, and they'll be willing to pay for it tomorrow.
Kevin Drum agrees with this assessment, and thinks this explains why Republicans in Congress are utterly opposed to every spending bill. But as I was explaining to Nat-Wu and Adam in an email, I don't think this is a strategy so much as a description of events. To quote myself:
Liberals think these things are good and that people will want to pay for them. We enact them and lo, we are right! It seems more a description of events than a plan for them.
That doesn't meant that Douthat isn't on to something about putting off to the future necessary tax increases. Given a choice I think most people will pay more in taxes rather than see substantial cuts to programs they like. I suppose you can deride this as salesmanship, but it's also out of political necessity. If you tried to enact these programs at the same time that you substantially raise taxes on the wealthy and marginally raise them on the middle class, you're pretty much ensuring the death of your proposal. I suppose that's political strategy, but it's not really a conspiracy to enact vast social safety programs that people don't know they want yet. It just happens to make it very difficult for Republicans to stop these programs from getting enacted, though that's largely because most Americans agree on the need for the programs.