Senator Roy Blunt, Republican of Missouri, called Mr. Adelson “a force of nature” in a statement following the announcement of his death, which was caused by complications of non-Hodgkin’s lymphoma, his company, Las Vegas Sands, said.
Mr. Adelson was a major supporter of Israeli causes, and Dr. Adelson, who was born in Israel and was the driving force behind the family’s involvement in conservative Israeli politics, is expected to remain active as the publisher of the free daily newspaper Israel Hayom. “Miriam will continue to make every decision that she makes as though he’s by her side,” said one person who knows the Adelsons and spoke on the condition of anonymity because the family is in mourning.
In the United States, the couple was a key source of support for the Republican Jewish Coalition, which remained a close ally of Mr. Trump throughout the course of his turbulent presidency. The Adelsons were among those who helped convince Mr. Trump to adopt a hard-line pro-Israel stance, which led to his decision in 2017 to relocate the American embassy from Tel Aviv to Jerusalem — a move that incensed Palestinians and led to unrest across the Middle East.
The couple was seated in the front row for the ribbon-cutting ceremony commemorating the move in May 2018. That day, Dr. Adelson described Mr. Trump as “the Truman of our time” in an extraordinary front-page editorial in The Las Vegas Review-Journal, which she and her husband had purchased in 2016.
His huge spending changed the contours of the battles for the Senate and House, as well as past Republican presidential nominating contests. In 2012, he funded a super PAC supporting Newt Gingrich that bloodied the eventual nominee, Mitt Romney, and gave Mr. Gingrich’s often quixotic campaign a longer shelf life than many expected it to have. But in the general election, the Adelsons invested millions more in another super PAC that aimed to help Mr. Romney defeat President Barack Obama.
For years, top Republicans sought Mr. Adelson’s approval and cash. In the 2016 presidential primary, Mr. Trump attacked his fellow Republicans for pursuing Mr. Adelson, in particular Senator Marco Rubio of Florida. “Sheldon Adelson is looking to give big dollars to Rubio because he feels he can mold him into his perfect little puppet. I agree!” Mr. Trump wrote on Twitter in October 2015.
Their relationship evolved over time. Once Mr. Trump became the apparent Republican nominee and the party started to unify around his renegade candidacy, Mr. Adelson agreed to back him.