Elon Musk’s lawyers approached a federal appeals court in Manhattan to throw out a 2018 provision from the billionaire’s consent decree with the Securities Exchange Commission that requires a Tesla lawyer to vet some of his tweets.

The filing made late on Tuesday said that the pre-approval clause was a “government-imposed muzzle’ and that it was inhibiting his speech on a variety of topics, according to a Reuters report. The court document went on to say that the SEC-sanctioned clause was a violation of the US Constitution and that it was undermining public policy. The filing said that the clause was “contrary to the American principles of free speech and open debate.”

The new appeal is an attempt to overturn part of a ruling made by U.S. District Judge Lewis Liman in April this year. Judge Liman had rejected the bid to throw out the decree altogether. At the time, Judge Liman had said that Musk’s argument was invalid because his company had now become, “in his estimation, all but invincible.” 

The SEC is expected to make its own  filing with the 2nd U.S. Circuit Court of Appeals in Manhattan. 

The 2018 decree was part of resolution of a lawsuit which accused the Tesla co-founder of defrauding investors with a tweet he had made in August that year saying that he had secured funding to take his company private, though there had been no talk of a buyout. Musk has said he wasn’t lying when he made the tweet. 

As part of the resolution, both Musk and Tesla had to pay $20 million in civil fines. He also gave up his position as the chairman of the electric car company.

In other news, Musk and his team of lawyers are currently gearing up for the five-day trial against Twitter on October 17. He will be trying to prove to a Chancery judge that his withdrawal from the $44 billion buyout of the social media company was based on Twitter’s lack of transparency about the number of spam and bot accounts on the platform.