The Senate health care legislation will include a government-run insurance plan, but states would be allowed to “opt out” of it, the majority leader, Harry Reid of Nevada, announced Monday afternoon.

The question of whether to include a government-run plan to compete with private insurers has been the most controversial topic in the effort by Mr. Reid and other Democratic leaders to meld two competing versions of the Senate health care legislation.

Democrats have been deeply divided. Supporters of the government plan, or public option, have been pushing to include it in the bill before it is brought to the Senate floor, meaning opponents would need 60 votes for an amendment to strip it out.

Opponents of the public option have argued that it should be left out of the bill and that supporters should be forced to offer an amendment to add it to the legislation. In either case, winning 60 votes would seem to be a steep hurdle.

Mr. Reid’s decision, made after nearly two weeks of deliberation, reflects a calculated gamble that the 60 Senate Democrats will stay united and vote in favor of a motion to bring the bill up for debate before the entire Senate.

If 60 senators refuse to support the bill including the government plan with a state opt-out, Mr. Reid would then have to regroup, make changes and try again. Some Democrats believe that liberal members of the party would not relent in their push to include the public option unless faced with such a clear defeat.

Mr. Reid worked through the weekend in an effort to secure votes. Among the Democrats who have expressed doubts about a public insurance plan are Senators Mary Landrieu of Louisiana and Ben Nelson of Nebraska.

Mr. Reid’s office did not release many details. In theory, states that wish to opt out of the public plan would have to adopt a law to do so, which would require agreement between the state legislature and the governor.

Even though Mr. Reid has announced his intentions on the public option, the bill is not yet ready to bring to the Senate floor.

Pieces of the legislation will be submitted to the Congressional Budget Office for cost analysis. A number of senators in both parties have said that they will not vote on the bill unless they have had time to review and comprehensive cost estimate.

Copyright 2009 The New York Times Company