President Donald Trump threatened to veto a Congressional bill that includes a provision to rename military installations named after Confederate leaders.

“I will Veto the Defense Authorization Bill if the Elizabeth ‘Pocahontas’ Warren (of all people!) Amendment, which will lead to the renaming (plus other bad things!) of Fort Bragg, Fort Robert E. Lee, and many other Military Bases from which we won Two World Wars, is in the Bill!” Trump tweeted on Tuesday evening.

The amendment was adopted by the GOP-led Senate Armed Services Committee last month with support from both Democrats and Republicans. The amendment was originally added to the annual defense policy bill by Sen. Elizabeth Warren (D-Massachusetts). The Pentagon would have three years to rename the military bases honoring Confederates and remove their names and rebel symbols from ships, aircraft, streets and other Defense Department property.

“American military bases that carry the names of Confederate generals are not named for heroes,” Warren said in a floor speech on Tuesday. “They are not named for men who risked their lives defending the United States and its soldiers. They are named for men who took up arms against the United States of America and killed American soldiers in the defense of slavery.”

Most Republicans did not oppose Warren’s amendment. Sen. John Cornyn (R-Texas) followed up on Trump’s tweet and said that the amendment could be modified to appeal to Trump.

“You know we’ve got a long way to go to get the NDAA bill done in the first place, and there’s a conference committee,” Cornyn told reporters. “So there’s many places along the way where we can modify that and hopefully in a way the President will agree to.”

Senate Armed Services Chairman Jim Inhofe (R-Oklahoma) noted that it will be months until the bill will get to the president’s desk, adding that they hope to change his mind till then.

“The president is serious. He is dead serious on this thing,” Inhofe told CNN. “Of course, he wouldn’t veto something until it reaches his desk. That probably is going to be sometime around November, so we have until now and November to make sure we overcome the reason for his veto.”