Sen. Ben Sasse, R- Neb., is firing back at Fox News' Sean Hannity after the TV pundit said "one the biggest mistakes" he ever made was supporting the conservative lawmaker.

"Sorry, Sean — you changed, not me. Some of us still believe in the Constitution," Sasse tweeted Thursday.

On Wednesday, the Nebraska senator took a shot at President Trump in a statement, asking whether he was "recanting of the oath you took on January 20th to preserve, protect, and defend the First Amendment?"

Sasse was expressing his dismay for the president's recent attacks against the press and questioning whether or not some networks are worthy of a broadcasting license.

Hannity, an ardent Trump supporter, tweeted in response: "One of the biggest mistakes in my career was supporting @BenSasse Just useless."

In addition to telling Hannity he "changed," Sasse went on to argue, "no president should play with censoring news they dislike."

Earlier this week Trump responded to reporting by NBC News about him proposing the U.S. nuclear arsenal increase nearly tenfold. "It's frankly disgusting the way the press is able to write whatever they want to write," Trump said.