CNN  — 

After declaring he was stepping away from the political spotlight, Elon Musk got right back in it.

As the Senate debated President Donald Trump’s “Big, Beautiful Bill” on Monday before a final vote, Musk issued a stark warning via his social media platform X.

“Every member of Congress who campaigned on reducing government spending and then immediately voted for the biggest debt increase in history should hang their head in shame! And they will lose their primary next year if it is the last thing I do on this Earth,” he wrote.

A few hours later he went further, declaring on X thatif the “insane spending bill passes, the America Party will be formed the next day.”

“Our country needs an alternative to the Democrat-Republican uniparty so that the people actually have a VOICE,” he wrote.

For weeks, Musk has railed against Trump’s policy bill, leading to a very public and ugly fight with Trump earlier this month. In a flurry of X posts several weeks ago, Musk had proposed starting a new political party.

That proposal resurfaced on Monday, when Musk said: “It is obvious with the insane spending of this bill, which increases the debt ceiling by a record FIVE TRILLION DOLLARS that we live in a one-party country – the PORKY PIG PARTY!! Time for a new political party that actually cares about the people.”

Musk’s resolution to support candidates who plan to launch primary campaigns against members of Congress is one of Musk’s most concrete political threats since leaving his post as a White House adviser. Musk spent more than $275 million to support Trump and other Republican candidates in the 2024 election. In late May he said in an interview he was planning to cut back on political spending, saying he has “done enough.”

According to Federal Election Commission filings, Musk’s political action committee, America PAC, last gave money in March to support two Republican candidates running in special elections in Florida – Randy Fine and Jimmy Patronis.

Musk has long supported closed borders, deportations and stopping illegal immigration, in line with the Trump administration.

But the domestic policy bill has appeared to trigger a rift between the Tesla CEO and the White House. Musk has argued that the Republican policy bill will increase the debt, calling it “debt slavery.”

The Senate bill would add nearly $3.3 trillion to the deficit over the next decade, according to a Congressional Budget Office estimate released Sunday. The Senate legislation costs more than the House-approved bill, which would add $2.4 trillion to the deficit over the next decade.

The Senate package contains deeper tax cuts fewer spending cuts and provisions that would raise revenue. The White House has argued the bill “slashes deficits” and the debt, while “unleashing economic growth.”

The Trump administration and certain Senate Republicans are opting not to include the cost of extending the 2017 Trump tax cuts in their calculations of the bill’s impact on the federal deficit.

Though Musk has said the loss of electric vehicle and solar energy subsidies and credits in the bill are not why he opposes the legislation, he has complained the bill “gives handouts to industries of the past while severely damaging industries of the future.”

CNN’s Tami Luhby contributed reporting.