The ad is part of a long-held strategy among campaign tacticians: elevate your most extreme rival, and peel away disaffected moderates from that rival’s party come November. Last week, Axios noted that the rise of far-right, Trump-aligned candidates could test this theory and that Democrats are “trying to engineer the rise of ultra-MAGA candidates they feel will be easier to defeat in a general election.”…

On Sunday, the CNN host Dana Bash asked Mr. Shapiro if it was “irresponsible” to boost a candidate like Mr. Shapiro “because you think you can beat him.”

It was not, Mr. Shapiro said. For weeks, Mr. Mastriano led the crowded Republican field, according to public and private polling, and Mr. Shapiro, who was uncontested for the Democratic nomination, said he was eager to have voters understand the choice they would soon face.

“What we did was start the general election campaign and demonstrate the clear contrast, the stark differences between he and I,” Mr. Shapiro said.