Mitt Romney: GOP senators 'increasingly likely' to call John Bolton to testify in impeachment trial
Former Govenor Mitt Romney speaking with supporters of U.S. Congresswoman Martha McSally at a campaign rally at The Falls Event Center in Gilbert, Arizona. (Gage Skidmore/Flickr)

John Bolton's book bombshell may have broken President Donald Trump's grip on the Republican Party.

The former national security adviser's forthcoming book "The Room Where It Happened" claims Trump explicitly tied Ukraine aid to an investigation of Joe Biden, and GOP senators are publicly saying they want him to testify during the impeachment trial.

“I think it’s increasingly likely that other Republicans will join those of us who think we should hear from John Bolton," said Sen. Mitt Romney (R-UT).

Romney and other Republicans voted to table a Democratic amendment last week, at the start of the trial, that would have added new testimony to the impeachment process -- but Bolton's revelations may force them to call witnesses.

Trump falsely claimed Monday morning that House investigators never called Bolton to testify.

In fact, Bolton did not appear for a scheduled deposition before the House impeachment inquiry, but has said he would comply with a Senate subpoena.