Will White House be big enough for Trump -- and Musk?

Donald Trump will be the one taking the presidential oath next week, but in some respects, billionaire Elon Musk might as well place his hand on the Bible too.

In an unprecedented relationship for modern US history, Trump will be heading into the White House shadowed by an advisor who is not only the world's richest person but matches the incoming president in terms of wild ambition, hard-right politics, and media influence.

Will the Oval Office be big enough for two outsized personalities, let alone the mountain of conflicts of interest trailing Musk?

It's a political marriage that was sealed by Musk's bankrolling of Trump's third tilt at the US presidency.

The duo have an extraordinary collective power over messaging, with Musk turning his X social media platform into a haven for right-wingers and Trump enjoying friendly coverage from an entire conservative media ecosystem.

They also share a love for provocative theatrics.

"Like Trump, Musk recognizes the value of getting attention for saying and doing things that some people see as outrageous... he likes challenging norms," said Margaret O'Mara, a history professor at the University of Washington.

Musk has made quite the impact with the once and future president, according to Peter Loge, director of George Washington University's School of Media and Public Affairs.

"Elon Musk is rich, and brash, and he is constantly reminding Donald Trump how wonderful Donald Trump is -- which are all things Donald Trump likes," Loge said.

- Cutting and slashing -

However, Lorenzo Castellani, a history professor at Rome's Luiss Guido Carli, warns that "the chances of friction being generated in the long run are high."

Musk has been named in charge of a plan to slash federal spending and regulations. The ambitious plans are popular with right-wing ideologues but the Trump camp has not explained how such sweeping changes would avoid conflicts of interest, given that Musk is a major government contractor.

Even before Trump's inauguration -- he takes the oath on January 20 -- Musk appears to be running into his first doses of political reality.

The Tesla and SpaceX boss had initially vowed to chop a highly improbable $2 trillion in government spending, but now says "we've got a good shot" at saving $1 trillion.

Even that would be a colossal undertaking, with the government's budget about $7 trillion overall -- making such dramatic cuts difficult without losing crucial services or benefits.

The South African native, 53, has appeared almost omnipresent with Trump since the November election.

Musk has joined Trump's meetings with business leaders and foreign delegations. The duo are frequently photographed dining together and even dancing together to campy classic "YMCA" on New Year's Eve.

According to Castellani, Musk's close relationship with the incoming president recalls those of the "robber barons" of the late 19th and 20th centuries -- men like Cornelius Vanderbilt, Andrew Carnegie and JP Morgan -- "who had enormous economic power and political influence."

Like his predecessors, Musk is using his political clout to protect his interests.

He has used X, formerly Twitter, to boost far-right movements and start online fights in Europe.

In Britain, where lawmakers adopted new restrictions on social networks, Musk has brutally attacked Prime Minister Keir Starmer including calling for his ouster.

He has repeatedly praised Germany's far-right party AfD, while criticizing the European Commission, as Brussels threatens X with a hefty fine.

- Tech bros -

Other businessmen have flocked to Trump's orbit, echoing Musk's libertarian, small government views.

But the rise of the American oligarchs is stirring tensions within the right, where "Make America Great Again" stalwarts see the wealthy powerbrokers as symbols of the very globalization they thought Trump was going to combat.

Silicon Valley businessman Vivek Ramaswamy, Musk's co-chair in the government efficiency effort, created a firestorm when he spoke out in defense of a visa program allowing highly skilled workers into the United States.

The son of Indian immigrants lambasted what he called an "American culture" that has "venerated mediocrity over excellence for way too long."

This did not sit well with traditional Trump backers.

"We welcomed the tech bros when they came running our way to avoid the 3rd grade teacher picking their kid's gender," Florida Republican Matt Gaetz wrote on social media.

"We did not ask them to engineer an immigration policy."