Mr. Obama should know from sad experience the pitfalls of seeking bipartisan cooperation from a Republican Party that has sloughed off most of its moderates and is dominated by its right wing. His stimulus package was supported by no Republicans in the House and only three Republicans in the Senate, so-called moderates whose support was won by shrinking the package below the size at which it would have done the most good.

Now the same sort of damaging retreat may be happening in the Senate Finance Committee. Three committees in the House and one in the Senate have used their Democratic majorities to approve liberal health reform bills. The only bipartisan negotiations are between a rump group of three Democrats and three Republicans on the Finance Committee who hail from largely rural states with small populations, namely Iowa, Maine, Montana, New Mexico, North Dakota and Wyoming. Somehow this small, unrepresentative group has emerged as the focal point for bipartisan health care reform.

The six have been working hard to reach agreement, but the concessions demanded by Republicans will most likely make the reform effort weaker and smaller. They could, for example, reduce the scale of the program and the subsidies for low-income people; drop the idea of a government-run insurance plan to compete with private insurers; and eliminate a requirement that employers offer coverage to their workers or pay a penalty.

Even if the group reaches an agreement, which is by no means certain, its compromise is unlikely to win support from a Republican Party that seems bent on delay. Leading Senate Republicans have seen little in the emerging compromise that they are willing to support.