GOP Sen. Susan Collins said she's open to calling additional witnesses for the Senate trial of President Donald Trump's impeachment, but stopped short of backing demands from Democrats for testimony to be set before the process begins.
The Maine Republican is considered a possible swing vote on deciding the rules for the Senate trial when it gets underway, likely next month. While Trump is all but certain to be acquitted in the Republican-majority Senate, it would only take four Republicans to side with Democrats to call additional witnesses who weren't part of the House impeachment inquiry.
Collins and Alaska Sen. Lisa Murkowski, another potential Republican wild card, both have expressed concern about the impartiality of their colleagues, including Senate Majority Leader Mitch McConnell's statements that he is coordinating closely with the White House on trial procedures.