Roughly 30 minutes after former President Donald J. Trump was shot at a rally in Pennsylvania on Saturday, Elon Musk backed his bid for the White House.

“I fully endorse President Trump and hope for his rapid recovery,” Musk wrote on X, the social media platform he owns, sharing a video of Trump raising his fist.

In more than 100 posts after the shooting, Musk further stepped up his political speech. And on Monday, after Trump announced that Senator J.D. Vance of Ohio would be his Republican running mate, Musk posted congratulations and said it was an “excellent decision by @realDonaldTrump”.

With those moves, Musk, 53, entered uncharted territory. He broke with tradition set by the leaders of other social media firms, none of whom have endorsed a candidate. By using X as a megaphone for his politics — posting to his 190 million followers — Musk also erased any air of neutrality for the platform.

Now, as the presidential election gets closer, Musk’s full-throated support for the Republican candidates raises questions about how their opponents can expect to be treated on this site.

“He can fashion the platform in his image,” said Gita Johar, a professor at Columbia Business School who studies consumer behaviour. “He’s got a huge following and makes no bones on where he stands on issues and politics.”

He has also turned the notion that the tech industry supports Democratic candidates on its head. For all the complaints that social media platforms have censored Trump and other Republicans in recent years, no senior executive at one of the companies has openly expressed a preference for a Democratic candidate.

Mark Zuckerberg, Meta’s founder, rarely posts about politics, and Jack Dorsey, the former Twitter chief, became more outspoken on the topic only after he stepped down three years ago.

Satya Nadella, Microsoft’s chief, and Sundar Pichai, Google’s chief, have also kept quiet about their political views on the companies’ respective social platforms, LinkedIn and YouTube.

Beyond the endorsement, a new super PAC designed to help Trump could draw support from Musk, The New York Times reported on Monday. The founding donors of the group, America PAC, include several wealthy tech entrepreneurs from Musk’s social circle.

Musk, X and the Trump campaign did not respond to requests for comment for this article.

“Arrogant billionaires only out for themselves are not what America wants or what America needs,” James Singer, a Biden campaign spokesman, said in a statement. “Elon knows Trump is a sucker who will sell America out.”