WASHINGTON — President Trump’s strong-arm negotiating tactics may have worked against business opponents but they are backfiring with Republican senators, who resent being bullied to vote with the president on health care and other issues and have the political clout to resist him, experts say.

“No matter how strong or dominant a personality the president has, he is going to have trouble taking on an American political institution as powerful as the U.S. Senate,” said Grant Reeher, a political science professor and director of the Campbell Public Affairs Institute at Syracuse University. “Senators have a strong sense of independence and sense of self that says ‘I don’t get pushed around that way.’ And they’re pushing back.”

In the last two weeks alone:

• Sen. Lisa Murkowski, R-Alaska, chairman of the Energy and Natural Resources Committee, helped defeat Trump-supported bills to repeal Obamacare despite reported threats from the administration that her vote could jeopardize Alaska’s economic future. The warnings were delivered by Interior Secretary Ryan Zinke, who must go before Murkowski’s panel for budget and staffing approval.

• Judiciary Chairman Chuck Grassley, R-Iowa, made it clear that his committee will not approve a new attorney general for Trump if he fires Jeff Sessions. Senators have rallied around the former Alabama senator amid blistering attacks against him by the president, who is angry that Sessions recused himself from the investigation of possible collusion between the Trump campaign and Russian officials.

• Majority Leader Mitch McConnell, R-Ky., said the Senate will not get rid of the legislative filibuster, despite continued tweets from Trump pressuring GOP senators to eliminate the rule in order to make it easier for the White House to push through its agenda.

“It’s stunning to think the president believes that this kind of pressure campaign is going to bring senators to the table when it is actually repelling them,” said Joshua Huder, a senior…