That would be a reasonable question since they seem to be possessed with irrational fears. According to the NYT, Senator John Ensign said that he voted against a public plan because it will eventually take over the insurance market: "Once it’s started, you will never get rid of it. Congress will subsidize it more and more, allow it to grow and grow.” There is no precedent for Congress providing the enormous subsides that would be needed to allow a bad public plan to displace better private insurance plans. This would almost certainly run into hundreds of billions a year or multiple trillions over a 10-year horizon. This means that Mr. Ensign either is concerned that the public plan will actually be a good plan or he alternatively he fears an event that is about as likely as invasion from Mars. The NYT could have made this point more clearly.
--Dean Baker