The death of Sheldon G. Adelson, the casino magnate who used his vast fortune to tip the balance of power in Washington over the last decade by helping Republicans take control of the House, the Senate and eventually the White House, adds another element of uncertainty for the party as it faces a bitter reckoning over President Trump’s legacy.
Already, the fallout over the deadly siege on the Capitol by Trump supporters last week has hit the Republican Party financially, with several blue-chip corporations like Marriott and Blue Cross Blue Shield announcing that they would suspend donations to members of Congress who supported Mr. Trump’s efforts to overturn President-elect Joseph R. Biden Jr.’s victory.
And while it seems likely that Mr. Adelson’s wife, Dr. Miriam Adelson, will continue with some of their family’s political giving, his passing Monday night at the age of 87 leaves Republicans without a benefactor whose donations were so crucial to the party’s success that only a small number of billionaires, like Charles Koch, rivaled his influence.
All told, Mr. Adelson and his wife have donated more than a half-billion dollars to G.O.P. campaigns and super PACs since 2010, according to federal records.
His absence could further complicate Republican efforts in 2022 to regain power in Congress, where they will be in the minority in both chambers once the results of the Georgia Senate runoff are formally certified later this month and Mr. Biden is inaugurated.
“The corporate giving backlash, along with the tragic passing of Sheldon Adelson, leaves a real void in the fund-raising plans for the 2022 cycle,” said Scott Reed, a veteran Republican strategist who has worked with the Adelsons and other major G.O.P. financiers.
Part of the concern for Republicans, Mr. Reed added, is that the Adelsons have been so singular a force in the party that there is no replacement. “A next generation of Sheldon-level giving does not readily exist,” he said.