Senate GOP leaders are trying to avoid defections in an anticipated vote next week on whether or not to allow for new witnesses in President Trump's impeachment trial and remain in close talks with those potential swing voters, according to Republican aides.

Allowing new witnesses would bring a wild-card factor to the trial, lengthen the process and potentially set up a protracted court fight over executive privilege.

GOP leaders are actively reaching out to Republican senators who could potentially defect – Sens. Susan Collins of Maine, Lisa Murkowski of Alaska, Lamar Alexander of Tennesse and Mitt Romney of Utah – and are trying to keep them in the fold, according to two GOP aides.

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With all eyes on these potential swing votes, Collins was overhead Thursday evening raising concerns about the access of press.

After the trial recessed for the dinner break, Collins and Murkowski had an animated conversation on the Senate floor and Collins pointed up at the reporters above her in the balcony.

The Maine Republican was overheard saying she didn’t want the journalists overlooking from the front row and thought it should be emptied.

Collins continued to look up at reporters, and Sen. John Thune, R-S.D., and Sen. Thom Tillis, R-N.C., joined the huddle. Reporters covering the historic trial are only allowed to bring pens and paper in the gallery, and typical tools of the trade – phones, cameras, computers and even smartwatches – are all banned.

As the trial continued into the night, Democrats re-upped their demands for new witnesses and documents to be entered into evidence, charging that the trial would be a "cover-up" without them. They need the help of four GOP senators to win the necessary majority vote.

But Republicans are actively trying to avoid any GOP defections. No new witnesses would mean a speedy trial and a quicker vote to acquit the president.

The swing GOP voters are under intense scrutiny in the Capitol as the 100 jurors weigh whether to remove Trump from office for obstruction of congress and abuse of power.

As Murkowski was darting to get to the impeachment trial on Thursday, she was asked if she was feeling any pressure. “Only to get upstairs,” she quipped before the elevator door closed.

Republicans argue that if the Democratic case for impeachment is so strong, they wouldn't need the Senate's help for extra witnesses to make their case.

"We are ready for the president's team to put their defense on," Sen. John Barrasso, R-Wy., said Thursday. "The president didn't have a chance to do that in the House. We have heard plenty from the House now. They say that they've had overwhelming evidence."

Trump's legal team says new witnesses aren't needed but would expect reciprocity if the Senate vote didn't go their way.

“If the other side were to get witnesses, we would have a series of witnesses, but we are nowhere near that process yet,” Trump lawyer Jay Sekulow said Thursday.

Trump himself raised the concern earlier this week about executive privilege and said there would be national security concerns if his former adviser John Bolton testified.

If the Senate votes in favor of getting witnesses and Trump administration communications related to withholding military aid to Ukraine, Trump's legal team could assert executive privilege -- setting off an unchartered court challenge.

Sekulow said that the administration was within its constitutional rights to withhold documents and blasted House Democrats for trying to shred the constitution.

Some GOP senators have promoted witness reciprocity and called for Hunter Biden to testify about what he was doing on the board of Ukrainian energy company Burisma, in exchange for Bolton testifying.

Sen. Josh Hawley, R-Mo., wouldn’t predict whether there would be GOP defections but said the caucus is in regular talks to keep tabs on where senators stand.

“There’s an ongoing conversation, informal, on what people are thinking. We are spending a lot of time together,” Hawley said.

With the Senate GOP leadership trying to avoid going down the witness path with Democrats, they are actively reaching out to potential defectors -- Murkowski, Collins, Alexander and Romney.

The four were "instrumental" in changing Majority Leader Mitch McConnell’s organizing resolution on the fly to allow more days for opening statements and avoiding middle-of-the-night arguments. There is a strategic effort to keep these four involved in the process, an aide told Fox News.

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A speedy trial and acquittal without witnesses and documents would benefit the White House, and GOP leaders are trying to avoid a spectacle.

“There’s a bunch of people on my side that want to call Joe Biden and Hunter Biden,” said Sen. Lindsey Graham, R-S.C. “I want to end this thing sooner rather than later. I don’t want to turn it into a circus."

Fox News' Jason Donner contributed to this report.