WASHINGTON — A growing majority of Americans – including a sharply increasing number of Republicans – oppose an outright repeal of Obamacare, according to a new McClatchy-Marist poll, signaling trouble for Republicans still hoping to dismantle the 2010 health care law.

Efforts to repeal and replace the law collapsed last week, after Republican lawmakers couldn’t agree on an alternative.

Sixty-five percent of registered voters either want to see the Affordable Care Act, commonly referred to as Obamacare, maintained as is or strengthened, a 7-point uptick over a February McClatchy-Marist poll that asked the same question. The new poll was conducted between March 22 and 27. Republicans ended their effort to pass a health care plan on March 24.

Among Republicans, support for repeal plunged. Fifty-seven percent said Obamacare should be completely repealed, but that’s an 11-point drop since the February McClatchy-Marist poll.

“These Republican numbers suggest at the base there has been some erosion,” said Lee Miringoff, director of the Marist College Institute for Public Opinion, which conducted the survey.

“Times have changed,” he said.

The number of those opposed to repeal dwarfed those who support weakening or completely doing away with the law. Twenty-six percent of registered voters responded they wanted Obamacare repealed all together, with another 7 percent saying they want it amended to do less.

Miringoff said the poll’s findings indicate Americans could potentially support changes to Obamacare – but only if that means widening the scope of its coverage.