Former National Security Adviser
John Bolton grabbed headlines Monday when he somewhat surprisingly said he was "prepared to testify" should the
Senate call him as a witness in the upcoming impeachment trial. But
Republican senators aren't quite sure if they want to hear from him.Bolton's long been considered a potentially crucial witness since several current and former State Department and national security officials said in previous testimony before the House that he was concerned by President Trump's efforts to pressure
Ukraine into investigating his domestic political rivals while withholding military aid from Kyiv.Sen. Marco Rubio (R-Fla.) dismissed the idea of issuing Bolton a subpoena, arguing the trial should be tied only to the evidence the articles of impeachment are based on. So, in that case, since Bolton didn't testify before the House, he shouldn't be able to testify before the Senate.It's reasonable to think Rubio and other Republican want to avoid a scenario in which Bolton does some damage to Trump's defense, but not everyone in the GOP thinks that's the only way Bolton's time in the witness box could play out. Sen. John Cornyn (R-Texas) thinks Bolton could actually help Trump, though he's iffy on whether he'd support a subpoena.