President Obama has said he will not sign a health care reform bill unless it's paid for. If it doesn't lower costs, he will suggest spending cuts to make sure the deficit doesn't grow. That's a promise he says he will keep. But what about future presidents and members of Congress?

The question is not exactly a hypothetical: Today's rush to send money to seniors gives us a pretty good idea of the answer. For the first time since 1975, the Social Security Administration has announced, seniors will not receive an annual cost-of-living adjustment in their Social Security benefits. The move makes good policy sense"”the formula used by the SSA shows the cost of living has not increased in the past year. But it's also politically unpopular. That's why members of Congress and the...