Republican political donors and strategists seeking a conservative alternative to Donald Trump in the presidential race aren’t rallying to the latest proposed candidate, Tennessee lawyer David French, according to people familiar with talks to recruit another contender.

Conservative activist Erick Erickson, a Trump critic, said on his radio show Wednesday that Mr. French—so unknown he didn’t have a Wikipedia page until Tuesday—isn’t the answer because he can’t raise enough money to be competitive and would give Mr. Trump a scapegoat if he loses the general election.

“If there is a viable third-party candidate on the ballot in a handful of states, it gives [Mr. Trump] somebody to blame” if he loses, Mr. Erickson said

Vin Weber, a former Minnesota congressman who backed the Jeb Bush and John Kasich campaigns for the nomination, also said Mr. French doesn’t measure up to the other candidates whom Bill Kristol, editor of the conservative Weekly Standard magazine, has tried to recruit, including 2012 GOP nominee Mitt Romney and Nebraska Sen. Ben Sasse.

“By putting out the names Sasse and Romney, [Mr. Kristol] set the bar a little higher,” said Mr. Weber. “So David French, who is a perfectly fine, distinguished guy, looks pretty small compared to what he had thought was coming.”