(CNN) High-profile Republican swing vote Sen. Susan Collins of Maine said Monday she likes to dig into the facts of a matter she is considering. That's why she said she's pushing to have a chance to call witnesses in the impeachment trial of President Donald Trump, should she feel after opening arguments they are needed.
"Obviously I would not be advocating for language to be included in the governing resolution if I did not anticipate at the end of hearing the case presented, and the q-and-a, that there might be a need for more information," said the veteran Maine senator who is working with a small group of Republicans to try to find a path forward on the issue.
A reporter noted that she had voted for witnesses during the Clinton impeachment trial and pressed for more investigations into the allegations against now Supreme Court Associate Justice Brett Kavanaugh.
"I tend to like information," she said.
Collins declined to say if the small group she's in talks with is as many as four senators, the number needed to compel testimony: "I am not going to answer that question."
When a reporter kept pressing, she responded exasperated.
"I am not going to go through this for the 80th time," she said, as an elevator door closed saving her from any more questions.
One of those senators Collins is talking to is Republican Sen. Lisa Murkowski of Alaska who said Monday she's been "working" to make sure the Senate trial includes a process to vote on having "witnesses or documents" if needed.
"I've been working to make sure that we will have a process so that we can take a vote on whether or not we need additional information, and yes that would include witnesses," Murkowski said.
Another key GOP senator open to witnesses is Sen. Mitt Romney of Utah who said he would like to hear at least from former Trump national security adviser John Bolton but won't decide until after opening arguments, a process advocated by Senate Majority Leader Mitch McConnell.
"I would like to hear from John Bolton and other witnesses but at the same time I'm comfortable with the Clinton impeachment model when we have opening arguments first and then we have a vote on whether to have witnesses," Romney said, adding that he would oppose Democratic efforts to call witnesses until after the opening arguments, something he said might confuse people who might think he opposes witnesses.
The question is whether those three, should they vote for witnesses, could bring on board at least one more Republican. Several senators up for reelection in purple states are considered possible votes for witnesses, as are a handful of retiring senators who may not be afraid of a political backlash if they do.
One of those retiring senators is Sen. Lamar Alexander, a Republican from Tennessee and close ally of McConnell, who told CNN's Manu Raju he is open to witnesses but also wants to wait until a mid-point in the trial to decide.
"Yes, I am," Alexander said when asked if he's open to witnesses. "What I think is important is we have a vote on whether we need additional documents and witnesses. And that would only be appropriate after we've heard the case and asked our questions."