Twitter filed a lawsuit Monday against Texas Attorney General Republican Ken Paxton, claiming that Paxton launched an investigation into the company as retaliation for Twitter banning Donald Trump, Politico reports.

“Twitter seeks to stop AG Paxton from unlawfully abusing his authority as the highest law-enforcement officer of the State of Texas to intimidate, harass, and target Twitter in retaliation for Twitter’s exercise of its First Amendment rights,” the company wrote in announcing the lawsuit, filed in the US District Court for Northern California.

Paxton has long criticized social media companies for, he claims, silencing conservatives who make false or incendiary statements on their platforms.  Paxton, however, only announced an investigation of Twitter, the favored outlet for Donald Trump.

“First Amendment rights and transparency must be maintained for a free online community to operate and thrive,” Paxton said on January 13th, five days after Twitter permanently deleted Trump’s account. “However, the seemingly coordinated de-platforming of the President of the United States and several leading voices not only chills free speech, it wholly silences those whose speech and political beliefs do not align with leaders of Big Tech companies.”

Twitter responded that the First Amendment allows for the private company to determine what’s appropriate to include on the platform, something, Twitter says, the government should be protecting.

“Instead, AG Paxton made clear that he will use the full weight of his office, including his expansive investigatory powers, to retaliate against Twitter for having made editorial decisions with which he disagrees,” the company said.