Elon Musk is no stranger to shaking up the political establishment. But this time, his rebuke hits especially hard – and close to home. Just days after parting ways with Donald Trump’s administration, the tech mogul has unleashed a blistering critique of the former president’s marquee legislation, labelling the sweeping tax and spending proposal a “disgusting abomination”.

Until recently, Musk had been a high-profile supporter of Trump’s economic platform, even serving within his inner circle to lead a cost-cutting initiative known as Doge – short for “department of government efficiency”. His mission: weed out waste and inefficiency across federal departments. That partnership came to an abrupt end on 31 May, after just 129 days in office.

Now, with the proposed “One Big Beautiful Bill Act” making its way through Congress, Musk’s public dissent has shifted from caution to condemnation. In a series of scathing posts on his social media platform X on 3 June, the Tesla and SpaceX CEO accused lawmakers of saddling Americans with “crushingly unsustainable debt” and described the bill as “outrageous” and “pork-filled”.

His message was unambiguous: “Shame on those who voted for it. You know you did wrong. You know it.”

A ‘big’ bill – a bigger backlash

At the heart of the controversy is a massive tax and spending bill, endorsed by Trump and narrowly passed by the House of Representatives last month. The legislation includes extended tax cuts from Trump’s 2017 economic reforms, increased military and border security funding, and an eye-watering lift to the national debt ceiling – raising it to US$4 trillion.

According to the nonpartisan Congressional Budget Office, the measure would add an estimated US$3.8 trillion to the federal government’s already bloated US$36.2 trillion debt. Musk warned that it could push the annual budget deficit alone to US$2.5 trillion.

Trump, who has dubbed it his “big beautiful bill”, sees the legislation as a cornerstone of his second-term agenda. But for fiscal hawks like Musk, it’s the economic equivalent of lighting a match in a dry forest. “This will massively increase the already gigantic budget deficit,” Musk posted, accusing lawmakers of betraying the American people.

The backlash has exposed fractures within the Republican Party. While some lawmakers remain aligned with Trump’s vision, others – especially deficit-minded conservatives – are breaking ranks. Senator Rand Paul of Kentucky has publicly vowed to oppose the bill, warning that the GOP “will own the debt once they vote for this”.

Trump swiftly lashed out, accusing Paul of having “very little understanding of the bill” and claiming that “his ideas are actually crazy”.

Yet even among the loyal ranks, Musk’s words seem to have struck a chord. Some Republican senators have echoed his concerns, privately admitting the bill could prove politically risky. But party leaders, including Senate majority leader John Thune, remain determined to “proceed full speed ahead”.

A reckoning at the polls?

Musk’s intervention isn’t just rhetorical – it’s political. Having previously vowed to bankroll campaigns supporting Trump-aligned candidates, he has now flipped the script. In what reads like a call to arms, Musk warned on X: “In November next year, we fire all politicians who betrayed the American people.”

That threat carries weight. Musk was a major donor to Trump’s campaign and commands significant influence over a growing base of tech-savvy, economically libertarian voters. His pivot could reshape the midterm election landscape, particularly if he follows through on promises to unseat pro-bill incumbents.

The Senate is expected to review and potentially revise the legislation in the coming weeks. Behind closed doors, members of the Senate Finance Committee are preparing to meet Trump at the White House to discuss making the bill’s corporate tax cuts permanent – a move that could further inflate the overall cost.

White House press secretary Karoline Leavitt dismissed Musk’s remarks, saying “the President already knows where Elon Musk stood on this bill.” She doubled down on Trump’s stance, calling it “one, big, beautiful bill” and confirming he’s “sticking to it”.

But as the legislation barrels forward, the tension between fiscal responsibility and political ambition is reaching boiling point. Musk’s sharp pivot from insider to critic has thrown a spanner in the works of the Republican agenda – and may signal a broader rebellion brewing among conservative voices who once sang from the same hymn sheet.

In Washington, the stakes couldn’t be higher. If the bill survives the Senate largely intact, it could reshape America’s fiscal landscape for years to come. If it collapses under the weight of internal dissent, it may not be just the bill that’s doomed – but the unity of the GOP itself.

For now, all eyes turn to Capitol Hill, where backroom negotiations and public showdowns will determine whether Musk’s warning is a storm in a teacup – or the first lightning strike in a Republican reckoning.