The health care reform initiative that Obama signed into law two years ago today has perhaps been more central than anything else to the larger arguments that have consumed the political conversation since Obama became president.

The debate over Obamacare has of course been marred by a whole lot of lying and paranoia (see panels, death), and by the unfortunate absurdity that Republicans only came to see the individual mandate at its core as a grave threat to American freedom after Obama employed it. And let’s not forget the infamous Jim DeMint vow that health reform would be Obama’s “Waterloo,” perhaps the perfect expression of conservative hostility to this presidency. The Great Health Reform Debate has been the root cause of some of the ugliest, most cynical, and most deranged garbage our politics has served up during the Obama era.

But at its best, the argument has been all about the true nature of liberty, the proper role and obligations of government, and the real meaning of the social contract. And it’s forced liberals to sharpen their case on all these matters.

Jonathan Cohn tries to engage the big argument on the merits:

In principle, is the basic obligation that comes with health care reform — to pay for a mutual protection scheme that some individuals might not find advantageous or desirable — really so novel?

Hardly. It’s an obligation most of us meet on a regular basis, every time we get a paycheck.

I’m speaking, of course, about Social Security and Medicare. Each program is a form of “social insurance” and each serves the same basic function: To protect us from financial shocks that we cannot anticipate or avoid...

The Affordable Care Act is also a form of social insurance. It, too, seeks to protect us from problems that we cannot anticipate or avoid: Illness or accident before we turn 65. To get that protection, we must contribute towards its cost — by obtaining a qualified health plan on our own or, failing that, paying a fee to the government...

So why is the Affordable Care Act such an unconscionable infringement of liberty, while those two other, more revered programs are not?

* What repeal of health reform would take away: Don’t miss N.C. Aizenman’s useful overview of all the provisions that could be taken away from millions of Americans if the Supreme Court strikes down the law. Absolute must read.

* Obama to lay low on second anniversary: Laura Meckler reports that Obama will not publicly participate in the celebration of the health law today:

With the law still unpopular with many Americans, the White House has concluded that it is virtually impossible to change negative public opinions, particularly if Mr. Obama is front and center, a senior administration official said. Instead, the White House wants to spotlight health-care officials and regular Americans who have benefited from the law, in hopes of draining politics from the issue. Involving Mr. Obama makes the matter more political and is therefore counterproductive to the long-term goal of boosting public support for the overhaul, the official said.

* Nancy Pelosi’s crowning achievement: Pelosi has faith that the courts will uphold the law and that it will endure. If it does stand, it’s worth recalling Pelosi’s central role in shepherding health reform through, as well as the fact that she’s spent much of her lifetime fighting for it.

* Why repeal could cut against Republicans: Chris Cillizza talks to GOP strategists who believe that repeal of the law could actually work against the GOP, by taking away something Republicans can rally against and driving Dem turnout through the roof.

* Romney can’t escape his health care dilemma: Speaking of the Obamacare debate typifying some of the worst our politics has to offer, Beth Reinhard details how Romney can’t run or hide from his little Romneycare problem.

Another irony at the heart of Obamacare’s second anniversary: The likely GOP nominee is probably the worst-positioned Republican of all to prosecute the case against it.

* Elizabeth Warren and gay marriage: A must-read from Steve Kornacki on how Warren’s embrace of marriage equality represents all of her virtues as a candidate, but also all the challenges she faces as a real progressive trying to appeal to blue collar swing voters.

* Romney’s bluster about China: John Harwood has a nice look at Romney’s chest-thumping about a supposed trade war with China, how it rings hollow coming from a former Bain capitalist, and why China experts think it’s all election-year sloganeering.

* Quote of the day: Taegan Goddard catches a great James Carville quote to Buzzfeed, on the Obama campaign’s view of Romney:

“I think their assessment is that Romney is much less a threat to them as events are a threat to them, and I agree with that. Romney cannot beat Obama, only events can beat Obama.”

* And can Romney Etch-A-Sketch away his pandering to crazy right? A great Paul Krugman column linking Romney’s endorsement of the Obama-wants-gas-prices-to-soar lunacy to the larger problems created by the reality-deprived right, and to the “The Paranoid Style in American Politics”:

If and when he wins the nomination, Mr. Romney will try, as a hapless adviser put it, to shake his Etch A Sketch — that is, to erase the record of his pandering to the crazy right and convince voters that he’s actually a moderate. And maybe he can pull it off.

But let’s hope that he can’t, because the kind of pandering he has engaged in during his quest for the nomination matters. Whatever Mr. Romney may personally believe, the fact is that by endorsing the right’s paranoid fantasies, he is helping to further a dangerous trend in America’s political life. And he should be held accountable for his actions.

I continue to think that the second he becomes the nominee, Romney will be widely granted the presumption that he didn’t really mean any of the stuff he said to get through the primary. All that’s just part of the game, you see.

What else?