Virginia state Sen. Amanda F. Chase (R-Chesterfield) has a firm claim to the title of the commonwealth’s most polarizing politician. She is a lawmaker so extreme that her censure by the state Senate this year, the first such action by that body in 34 years, was opposed by just eight of her 18 Republican peers, as well as herself. She is also Republican gubernatorial candidate Glenn Youngkin’s highest-profile surrogate, and recently, his sidekick on the campaign trail.

Campaign compacts are often alliances of convenience born of opportunism, including in the current closely fought contest between Mr. Youngkin and Democrat Terry McAuliffe, who is running to regain his former job. Ms. Chase, who revels in giving offense, and Mr. Youngkin seem temperamental opposites. Nonetheless, Mr. Youngkin has invited her help, including in recent joint appearances; no other surrogate for his campaign attracts such attention or feeds off such notoriety. So it’s fair to wonder whether the woman who calls herself “Trump in heels” would play an influential role in a Youngkin administration if he becomes Virginia’s 74th governor.

If Ms. Chase’s loathsome comments bother Mr. Youngkin, he doesn’t let on. Although he said, once, that he doesn’t think fraud occurred in past state balloting and doesn’t expect it this year, he seems content as she rattles on conspiratorially about Democrats’ plans to steal the November elections, much as she says, repeatedly, that they stole last year’s from President Donald Trump.

He appears untroubled that she attended the Jan. 6 rally before the storming of the U.S. Capitol, or by her subsequent remark that the insurrection was staged by “patriots who love their country.” She also blamed antifa or Black Lives Matter “agents of destruction” for the assault and violence that day, a lie dismissed as false by the FBI, among others.

Her conduct and remarks earned Ms. Chase the censure of her state Senate colleagues, on a 24-to-9 vote, based on what the official resolution called her “conduct unbecoming of a Senator.” Separately, her fellow Senate Republicans withdrew her last remaining committee assignment, effectively rendering her an outcast in the party. Mr. Youngkin was not yet then the Republican gubernatorial nominee, but he had ample opportunity to repudiate her — they were rivals for months this year for the nomination — and did not, even as other GOP figures did.

Mr. Youngkin has remained similarly mum on Ms. Chase’s other obnoxious public musings this year. She said the murder conviction of former Minneapolis police officer Derek Chauvin in the death of George Floyd made her “sick,” and asserted that Democratic state Sen. Jennifer L. McClellan, who contested her party’s gubernatorial nomination, was unfit to represent Virginians because of her leadership role in the legislature’s Black Caucus. That was a racist remark.

She is beyond the pale; divisiveness is her brand. Yet it is precisely her extremism that dovetails with Mr. Youngkin’s two-faced electoral strategy, which seeks simultaneously to court his party’s Trump-loving core while appealing to suburban moderates with standard GOP tax-cut talk. He hopes swing voters elsewhere won’t notice. They should.