If you've been following the Democratic presidential primary race closely, you know that Hillary Clinton and Barack Obama have been going back and forth on the relative merits of their respective health care plans.  And the big point of contention has been whether an "individual mandate" is necessary for achieving universal coverage, at least in the short term. 

An individual mandate is a requirement that everybody obtain insurance either by purchasing it or signing up for a public program like Medicaid.  Clinton has a mandate in her plan, saying it's the only way to make sure everybody ends up insured.  Obama does not have a mandate, saying he wants to get his other reforms in place first -- making sure, among other things, there's actually affordable insurance available.  Then, he says, he can evaluate whether a mandate is even necessary.

Now John Edwards is getting into the scrum. Like Clinton, Edwards has always said he'd call for a mandate but was generally vague about how, exactly, he proposed to have government enforce it.  Yesterday, while campagning in New Hampshire, he said a little more. According to an ABC News account, Edwards said during a speech that "Every time you go into contact with the healthcare system or the govenment you will be signed up."  Then, during a press conference, he elaborated thusly:

Basically every time [people] come into contact with either the healthcare system or the government, whether it's payment of taxes, school, going to the library, whatever it is they will be signed up.

A reporter asked Edwards what would happen if somebody wouldn't sign up.  "You don't get that choice," he responded.

This explanation still leaves a lot unexplained.  A key question (maybe the key question) in designing a mandate is what happens to people who don't heed it.  If the penalty for non-compliance is just a minor fine, a lot of people will inevitably ignore the mandate, figuring it's cheaper to pay a few hundred bucks a year than to buy insurance. If the fines are sufficiently severe, then most people will probably comply.   But, of course, imposing such fines is also a lot more controversial politically -- which, presumbly, is why Clinton has avoided getting too specific and even Edwards is filling in the details slowly (thereby giving Obama an opportunity to question how solid their respective promises of universal coverage really are).

Still, yesterday's statements put Edwards in the thick of this latest health care tussle -- which, frankly, is where he belongs.  He was the first candidate this election cycle to put out a universal coverage plan -- a move that may well have stretched the boundaries of debate.   And it happens to be a very good plan, virtually identical to the one Clinton has since outlined.

As for the broader question at the heart of the policy dispute -- how much mandates really matter -- that's a complicated and legitimate issue.  I'll try to say something more concrete about it soon, particularly since I seem to have played a bit part in this debate already.

In the meantime, I'd recommend reading what Ezra Klein had to say about this issue yesterday.

--Jonathan Cohn