Elizabeth Edwards has cancer. John McCain has had cancer in the past. Last weekend, Mrs. Edwards bluntly pointed out that neither of them would be able to get insurance under Mr. McCain’s health care plan.

It’s about time someone said that and, more generally, made the case that Mr. McCain’s approach to health care is based on voodoo economics  not the supply-side voodoo that claims that cutting taxes increases revenues (though Mr. McCain says that, too), but the equally foolish claim, refuted by all available evidence, that the magic of the marketplace can produce cheap health care for everyone.

As Mrs. Edwards pointed out, the McCain health plan would do nothing to prevent insurance companies from denying coverage to those, like her and Mr. McCain, who have pre-existing medical conditions.

The McCain campaign’s response was condescending and dismissive  a statement that Mrs. Edwards doesn’t understand the comprehensive nature of the senator’s approach, which would harness “the power of competition to produce greater coverage for Americans,” reducing costs so that even people with pre-existing conditions could afford care.