Sen. John McCain is in Des Moines today to unveil his health-care proposal, which emphasizes market-based competition to deliver services at a lower cost. The plan is built around refundable tax credits — $2,500 for individuals and $5,000 for families — as an incentive to buy health insurance.

Reforming the tax code is the key ingredient of any reform, and it’s encouraging to see McCain embrace that approach. During a conference call with bloggers this afternoon, he explained that the thrust of his proposal is to give individuals more responsibility over their health-care choices and reduce the role of employers.

Of course, the current debate taking place in Congress illustrates the stark contrast between McCain’s approach and what liberals are trying to do with health care in America. When I asked McCain about the State Children’s Health Insurance Program (SCHIP), he expressed vehement opposition to the $35-billion expansion that would cover adults, illegal aliens or families earning up to $83,000.

I’ll give the American people some straight talk. Thinking that you’re going to pay for it with a $1 tax increase on tobacco is voodoo. All I can say is that the lesson we should always learn is when we expand government, we’re going to expand government.

Conservatives should demand the same kind of answer from all Republican presidential candidates.