Former national security adviser John Bolton said Wednesday he was surprised that Senate Republicans rejected his offer to testify in President Donald Trump’s impeachment trial. But he said that even if he had testified, it wouldn’t have changed the outcome of the trial because of how House Democrats handled their investigation.

"I think the House committed impeachment malpractice," Bolton said at an event at Vanderbilt University with Susan Rice, who was national security adviser during the administration of former President Barack Obama. "The process drove Republicans who might have voted for impeachment away" because "it was so partisan," he said.

But, he added, "my testimony would have made no difference to the ultimate outcome."