Congress has been formally debating health care reform for almost nine months. And the country, as a whole, has been debating it for years. But now that the last congressional committee with jurisdiction has approved legislation, lawmakers are confronting the essential conundrum that's bedeviled this issue all along: Their desire to expand health insurance coverage exceeds their willingness to pay for it. As deliberations move to the House and Senate floors, then on to conference-committee negotiations, something has to give.

You can see the dilemma in the bill that the Senate Finance Committee passed last week. The Congressional Budget Office (CBO) determined that the Finance bill both pays for itself and would actually reduce federal spending (relative to what it would...