The "public option" is dangerous not for what it might do but for what it allows the politicians not to do.

From the start, the Obama administration has said that health-care reform has to make health care both more accessible and less costly . If Congress does the first without the second -- guarantees a new entitlement without controlling costs -- it will bankrupt us, because health-care costs are rising faster than the overall economy is growing.

So far, though, that seems to be where Congress is headed, for two reasons: First, no one knows for sure how to control costs; and, second, the reforms that are likeliest to work are politically unpalatable.

What are those reforms? The most logical big thing Congress could do would be to tax, as income,...