John Weaver, a longtime Republican strategist and co-founder of the prominent anti-Trump group the Lincoln Project, has for years sent unsolicited and sexually provocative messages online to young men, often while suggesting he could help them get work in politics, according to interviews with 21 men who received them.

His solicitations included sending messages to a 14-year-old, asking questions about his body while he was still in high school and then more pointed ones after he turned 18…

Mr. Weaver sent overt sexual solicitations to at least 10 of the men and, in the most explicit messages, offered professional and personal assistance in exchange for sex. He told one man he would “spoil you when we see each other,” according to a message reviewed by The New York Times. “Help you other times. Give advice, counsel, help with bills. You help me … sensually.”

Lincoln Project leaders, in their first extended comments about Mr. Weaver, said they had not been aware of such allegations until this month, when a magazine article and an open letter on Twitter from a data analyst named Garrett Herrin accused Mr. Weaver of grooming young men online.