Political leaders have shunned the Alternative for Germany. But on his social media platform X, Mr. Musk is pitching the party as mainstream.

Elon Musk and a German far-right leader appeared to come to a truly bizarre agreement during a livestreamed X chat Thursday: Adolf Hitler was a communist. Musk had been plugging the chat with the AfD (Alternative for Germany) co-leader Alice Weidel for days,

The publicity was a potential boon for AfD, which has been frozen out of mainstream politics, in part, because its leaders have downplayed Nazi atrocities.