WASHINGTON  Given hardening Republican opposition to Congressional health care proposals, Democrats now say they see little chance of the minority’s cooperation in approving any overhaul, and are increasingly focused on drawing support for a final plan from within their own ranks.

Top Democrats said Tuesday that their go-it-alone view was being shaped by what they saw as Republicans’ purposely strident tone against health care legislation during this month’s Congressional recess, as well as remarks by leading Republicans that current proposals were flawed beyond repair.

Rahm Emanuel, the White House chief of staff, said the heated opposition was evidence that Republicans had made a political calculation to draw a line against any health care changes, the latest in a string of major administration proposals that Republicans have opposed.

“The Republican leadership,” Mr. Emanuel said, “has made a strategic decision that defeating President Obama’s health care proposal is more important for their political goals than solving the health insurance problems that Americans face every day.”