Even senators from the same state are taking different positions. Whereas Ernst voted for Warren’s amendment, Senate President Pro Tempore Chuck Grassley (R-Iowa) said Monday he would likely support Hawley’s change to the provision.

“I don’t want to rewrite history,” Grassley said, while acknowledging he had “not absolutely made up [his] mind.”

Senate Armed Services Committee Chairman Jim Inhofe (R-Okla.) agrees with Hawley that Warren’s amendment should be softened to give the secretary of Defense discretion over whether to change base names or not. He also wants to give state and local authorities direct say on proposed changes in their communities.

But the biggest driving force for preserving the status quo is President Trump, who last week urged Senate Republicans “not to fall for this!”