WASHINGTON  President Obama on Monday issued his own blueprint for a health care overhaul, challenged Republicans to come forward with their ideas and laid the groundwork for an aggressive parliamentary maneuver to pass the legislation using only Democratic votes if this week brings no progress toward a bipartisan solution.

In laying out for the first time the details of what he wants in the legislation, Mr. Obama set in motion a new round of maneuvering intended to bring a bitterly divisive yearlong clash to a conclusion. With the two parties scheduled to meet Thursday for a televised session on the health care overhaul, Mr. Obama appeared intent on forcing the Republicans into a choice: either put a specific alternative on the table, giving Democrats a chance to draw pointed contrasts between the parties’ approaches, or be cast as obstructionist and not serious about addressing an issue of great concern to voters.

The initial Republican response suggested the two parties are more likely headed toward a showdown than toward a deal. Representative John A. Boehner of Ohio, the House Republican leader, said Mr. Obama had “crippled the credibility” of Thursday’s meeting by proposing “the same massive government takeover of health care” that Americans had already rejected.

The bill, which the White House estimates would cost $950 billion over a decade, aims to fulfill Mr. Obama’s goals of expanding coverage to millions of people who are uninsured, while taking steps to control soaring health care costs. It sticks largely to the version passed by the Senate in December, but offers some concessions to House leaders who have demanded more help for middle-class people.