Barack Obama's campaign is already running two television ads that make the case against John McCain on health care.

Today the Obama campaign will send volunteers out knocking on doors in ten Iowa cities to "talk about the differences between the Obama plan to make health care affordable and the McCain plan to tax employees' health benefits." I assume canvassers will be doing the same thing in other states.

I think it's smart for Obama to push this point about McCain wanting to tax health care benefits, but don't imagine that this is the only thing wrong with McCain's health care plan.

Elizabeth Edwards made a strong case against other aspects of McCain's plan this spring. (See also this article about her speech to the annual meeting of the Association of Health Care Journalists.) One of the biggest problems is that insurers could continue to exclude people with pre-existing conditions, including cancer survivors like McCain and Elizabeth Edwards.

Whether or not you canvass today, you may want to bring up these points as well as the tax issue if you talk with undecided voters about the difference between Obama and McCain on health care reform.