After a weekend of intense consultations with fellow Democrats, Senate majority leader Harry Reid has decided he has the votes to get a health-reform bill with a public option to the Senate floor. "I believe we clearly will have the support of my caucus to move to this bill and start legislating," Reid declared at a news conference Monday afternoon. The real question, however, is whether he has the votes it will take to get it out of the chamber.

The bill that Reid intends to introduce would include a public option with a so-called "opt-out" provision, giving states the ability to decide not to offer a small share of their residents the chance to buy into a government-run health-insurance alternative. Ostensibly, such a provision would appeal to moderates, who object to the...