Though Mr. Haslam has said he felt under no time pressure, the state faces a Jan. 1 deadline to qualify for the first $300 million in Medicaid money for the coming year. The Tennessee Hospital Association, the state Chamber of Commerce and Democrats say Mr. Haslam cannot afford to wait much longer.

The National Conference of State Legislatures says that as of this month, 21 states, all of them with Republican governors or Republican-dominated legislatures, have announced that they would not expand Medicaid, while 27 others, plus the District of Columbia, have already approved an expansion or indicated that they would do so. The election this month of Terry McAuliffe, a Democrat and a supporter of the health care act, as governor of Virginia makes it likely that the state will join the expanders.

That leaves just Tennessee and Pennsylvania, where Gov. Tom Corbett has also asked the Obama administration for permission to use federal funds to buy private health insurance for the uninsured poor, on the fence.

A son of the Knoxville, Tenn., founder of Pilot Flying J, the nation’s largest chain of truck stops and travel centers, Mr. Haslam remains a popular figure in his state. A May poll by Vanderbilt University’s Center for the Study of Democratic Institutions showed him with a 63 percent approval rating. The same poll, however, found that 60 percent of respondents favored the expansion of Medicaid in the state.

Mr. Haslam, 55, ran for mayor of Knoxville in 2003 as a pro-business conservative, and was re-elected in 2007 with 87 percent of the vote. In 2010, he ran for governor, winning with 65 percent of the vote. He is up for re-election next year and is a prohibitive favorite, with nary a primary challenger in sight and no strong Democratic challenger yet, either.

In Tennessee, opposition to expanding Medicaid has come largely from Republican officeholders and conservative groups. Arrayed on the other side are the Tennessee Hospital Association and other medical groups, the Tennessee Chamber of Commerce and Industry and local chambers across the state, several antipoverty organizations and the Democratic opposition.