WASHINGTON — The most powerful part of President Biden’s climate agenda — a program to rapidly replace the nation’s coal- and gas-fired power plants with wind, solar and nuclear energy — will likely be dropped from the massive budget bill pending in Congress, according to congressional staffers and lobbyists familiar with the matter. Senator Joe Manchin III, the Democrat from coal-rich West Virginia whose vote is crucial to passage of the bill, has told the White House that he strongly opposes the clean electricity program, according to three of those people. As a result, White House staffers are now rewriting...