Advisers to Mr. Obama said they expected him to take swift action on two fronts. First, they said, he will probably revoke a Bush administration directive that sharply restricted states’ ability to expand the State Children’s Health Insurance Program. In addition, they said, he will support Congressional efforts to expand the program before March 31, 2009, when at least 42 states are projected to exhaust their allotments of federal money.

Ronald F. Pollack, the executive director of Families USA, a liberal-leaning consumer group that has worked closely with Congress and the Obama team, said, “The prospects for meaningful health care reform have never looked better.” Among Mr. Obama’s health care strategists, Mr. Pollack said, are former Senator Tom Daschle; Jeanne M. Lambrew, a former Clinton aide; Neera Tanden, who was director of domestic policy for the Obama campaign; and Representative Rahm Emanuel, who will be White House chief of staff.

In his plan, Mr. Baucus makes these proposals:

¶People age 55 to 64 should be able to buy Medicare coverage if they do not have access to a public insurance program or a group health plan. More than four million people in this age group are uninsured.

¶Medicaid would be available to everyone below the poverty level, providing at least seven million more people with access to the program. In many states, adults with incomes well below the poverty level  $17,600 for a family of three  are ineligible for Medicaid.

¶The State Children’s Health Insurance Program would be expanded to cover all uninsured youngsters in families with incomes at or below 250 percent of the poverty level ($44,000 for a family of three). This would raise the income limit in about half the states.

Mr. Baucus would also make it easier for many legal immigrants to qualify for Medicaid and the children’s health program. Under current law, such immigrants are generally barred from the programs in their first five years in the United States. He would lift that ban.