I didn't think that was an especially strong statement by Obama just now. He had two good one-liners: "One party doesn't get to shut down the government just to refight the results of an election," and "You don't get to extract a ransom for doing your job."
Those are good lines, but they were completely devoid of context. I can imagine someone just tuning into all this saying "Huh? Refight the election? What's he talking about?"
Here's what he should have said: "The Republicans hate the health care law. That's their right. They had three shots at stopping it. The first was in Congress, back when it passed. They moved heaven and earth to stop it, and they couldn't. They didn't have the votes. That was strike one.
"Then they said, 'Okay, we'll see you in court.' So they took the law to the Supreme Court. And they lost again. Strike two. Then, after that, they had a presidential candidate who ran against me. And he said to America, 'Forget strikes one and two. Elect me, and I'll repeal this monstrosity. And he lost. So that was strike three.
"Well, three strikes and you're out. You don't get to lose a political battle three times and then later come back and say, 'We're going to shut the government down if you won't change this law that we failed to stop three times.' I'd like conservative Americans to imagine what they'd have thought if Nancy Pelosi, upon becoming speaker in 2007, had threatened to shut down the government unless President Bush agreed to raise the top tax rate back up to the Clinton-era rates. Conservatives would have been outraged, and rightly so. The right response then, in that hypothetical, is the right response today: You want to change a law that passed that you don't like, go out and win some elections and overturn it. Write a new law. That's how it works. Don't threaten our economy, force hundreds of thousands of people to go without paychecks, bring the one-quarter or so of the economy that's driven by the federal government--contracts and so forth--to a standstill."
The polls say more people will blame the Republicans, but they aren't as clear-cut as they ought to be. Obama still needs to sell the Democratic position. Otherwise, people who don't know any better won't understand why the Democrats are right not to negotiate. He'll need to do better over the next few crucial days if a shutdown does happen.