The assurances have been conveyed in response to a highly delicate campaign by Mr. Romney and his top Jewish financial supporters to dissuade Mr. Adelson from adding to the $10 million that he and his wife have given to a pro-Gingrich “super PAC,” Winning Our Future, that has been tearing into Mr. Romney through television advertising.

Several people who have spoken with Mr. Adelson over the past two weeks said he would most likely continue to help the group as long as Mr. Gingrich remained in the race. But, they said, he is concerned that additional deep-pocketed donors have not joined him. And, they said, his affection for and loyalty to Mr. Gingrich, who met with him here on Friday, have not blinded him to the reality that the nominating contest is tilting in Mr. Romney’s favor…

“He saw a friend who needed and wanted help,” said an associate who talks to Mr. Adelson regularly, speaking on the condition of anonymity to avoid upsetting him. “I don’t think it’s likely that he’s going to fund Newt’s death march to Tampa,” the site of the Republican National Convention, “but if there is a realistic perception that he can help make his candidacy viable, he will.”…

Fully cognizant that Mr. Adelson is an important factor in determining when Mr. Romney can turn his focus away from Mr. Gingrich and more fully toward Mr. Obama, Mr. Romney and his top financial advisers have been pursuing a careful strategy of outreach to Mr. Adelson.