“The Democrats, their strategy is outrage,” he said. “I get that strategy. I lived that strategy. It’s a unifying strategy to be outraged at the other guy. The hard part is when you get in and have to deliver.”

Jenny Beth Martin, the president and co-founder of the Tea Party Patriots, said the group’s email blasts against Obamacare still trigger hundreds of responses from activists angry about it. The group helped make more than 100,000 phone calls over 48 hours when the House was voting on its bill in the beginning of May to repeal and replace.

But, she said, “We’re not yet on the yes side with what the Senate is doing.”

Grass-roots activists like Pat Daugherty, who once marched on Washington against Obamacare, now sound as disgusted with Republicans in Congress as they were in the early days of the Tea Party, when they helped primary challenges against lawmakers they derided as “Republicans in Name Only.”

“Every Republican in Congress ran on repealing Obamacare,” said Ms. Daugherty, a retired university administrator in Athens, Ga. “Why do we suddenly have a hard time repealing Obamacare when Republicans are in the majority?

“I know a lot of conservatives who are more upset with Republicans than with Democrats,” she said.

David Zupan helped organize Tea Party groups in Ohio against the Affordable Care Act, which he blamed for driving up health care costs and forcing him to shutter his technology support business. Before the law, he said, he paid $910 per month to insure him and his wife, with a $750 annual deductible. When he renewed his policy last year, he said, the rates had increased to $2,845 per month, with a $3,500 deductible.

Mr. Zupan had hoped to confront Senator Rob Portman over the recess to demand that he and his fellow Republicans push for a full repeal. Mr. Portman has expressed concern that the Senate bill would roll back Medicaid too far, particularly jeopardizing treatment for opioid addiction. But Mr. Zupan gave up after being unable to figure out where Mr. Portman would be.

Mr. Zupan, too, expressed a certain resignation with Republicans.

“Nothing they’re going to do to this bill is going to make it better,” he said.