Not only could Mr. Biden be forced to be in D.C. at a critical moment in the presidential campaign, but so could many of his chief rivals — the half-dozen senators also vying for Democrats’ presidential nomination, impeachment experts said.
For that matter, if the House chooses to impeach Mr. Trump on charges stemming from the special counsel’s Russia investigation, aides said it could open the door to witnesses such as fired FBI Agent Peter Strzok or even major figures from the Obama administration.
Republicans have a majority in the upper chamber, giving them full control over what an impeachment trial would look like.
Sen. Lindsey Graham, South Carolina Republican and chairman of the Senate Judiciary Committee, said this weekend that the GOP would certainly force the whistleblowers who have accused Mr. Trump of improper behavior in his phone call with the Ukrainian president to testify publicly.
He also suggested Rep. Adam B. Schiff, the California Democrat who Mrs. Pelosi has spearheading the impeachment push right now, could become a witness in any impeachment trial given revelations he hid interactions with one of the whistleblowers.