The launching of a House impeachment inquiry against President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE is raising the prospect of a Senate trial — unnerving senators already anxious about an election-year battle where the Senate majority could be up for grabs.

The worries cut both ways for Democrats and Republicans in the Senate.

Senators in both parties predict impeachment will further polarize the electorate, a troubling development for Republicans running in states won by Democrat Hillary Clinton Hillary Diane Rodham ClintonBloomberg rolls out M ad buy to boost Biden in Florida Hillicon Valley: Productivity, fatigue, cybersecurity emerge as top concerns amid pandemic | Facebook critics launch alternative oversight board | Google to temporarily bar election ads after polls close Trump pledges to make Juneteenth a federal holiday, designate KKK a terrorist group in pitch to Black voters MORE in the 2016 presidential race such as Sens. Cory Gardner Cory Scott GardnerBreaking the Chinese space addiction Trump dumbfounds GOP with latest unforced error Billionaire who donated to Trump in 2016 donates to Biden MORE (R-Colo.) and Susan Collins Susan Margaret CollinsDemocratic senator to party: 'A little message discipline wouldn't kill us' Poll: 57 percent of Americans think next president, Senate should fill Ginsburg vacancy On The Trail: Making sense of this week's polling tsunami MORE (R-Maine).

Yet for GOP candidates running in states where Trump has a higher approval rating, such as Sens. Thom Tillis Thomas (Thom) Roland TillisOvernight Energy: Trump officials finalize plan to open up protected areas of Tongass to logging | Feds say offshore testing for oil can proceed despite drilling moratorium | Dems question EPA's postponement of inequality training On The Trail: Making sense of this week's polling tsunami Feds say offshore testing for oil can proceed despite drilling moratorium MORE (N.C.), Joni Ernst Joni Kay ErnstOn The Trail: Making sense of this week's polling tsunami Tillis appears to reinforce question about COVID-19 death toll The power of incumbency: How Trump is using the Oval Office to win reelection MORE (Iowa) and Mitch McConnell Addison (Mitch) Mitchell McConnellDemocratic senator to party: 'A little message discipline wouldn't kill us' House to vote on resolution affirming peaceful transition of power Republican lawyers brush off Trump's election comments MORE (Ky.), the polarized electorate could help drive Republicans to the polls. ADVERTISEMENT

And impeachment proceedings could spell doom for Sen. Doug Jones, a Democrat up for reelection in Alabama, one of the nation’s most pro-Trump states.

Jones told The Hill on Wednesday that he’s not thinking about the impact on his reelection.

“It’s not a good day for the country when any impeachment inquiry is opened but the fact is we have to get facts out. That’s the main thing I pushed for,” Jones said. “The transcript is very troubling."

“This is not about an election,” he added. “This needs to be talked about [in terms of] the security of the country.”

Senate Republicans publicly defended Trump on Wednesday after the White House released a readout of his July 25 call with Ukrainian President Volodymyr Zelensky, but a number are also privately concerned about his efforts to pressure Zelensky to investigate Democratic presidential candidate Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE.

Very few are willing to challenge Trump publicly or criticize him behind closed doors with fellow GOP lawmakers.

Sen. Mitt Romney Willard (Mitt) Mitt RomneyCrenshaw looms large as Democrats look to flip Texas House seat The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election Trump dumbfounds GOP with latest unforced error MORE (Utah) was the only Senate Republican to speak up at a lunch meeting of the Senate GOP conference Wednesday. He said he was troubled by the White House’s call record, according to colleagues in the room. ADVERTISEMENT

“Clearly what we’ve seen from the transcript itself is deeply troubling,” Romney told reporters earlier in the day.

Romney was rebutted at the closed-door meeting by Senate Judiciary Committee Chairman Lindsey Graham Lindsey Olin GrahamLincoln Project mocks Lindsey Graham's fundraising lag with Sarah McLachlan-themed video The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election Trump dumbfounds GOP with latest unforced error MORE (R-S.C.), a close Trump ally.

“I said I’m underwhelmed. I’m not troubled. I don’t think there is anything remotely quid pro quo,” Graham said, summarizing his remarks in the meeting defending Trump.

He described the mood by other Republicans in the room as “relief” when they saw the details of transcript.

Graham, who was given a preview of the Trump-Zelensky transcript from Attorney General William Barr Bill BarrFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Why a backdoor to encrypted data is detrimental to cybersecurity and data integrity FBI official who worked with Mueller raised doubts about Russia investigation MORE on Tuesday, said he had no intention of pursuing the matter.

“I don’t want to turn the Senate into a circus,” he said. “I think there’s a belief among Republicans [that] Democrats have lost their minds when it comes to Trump.”

Other Senate Republicans were less vocal than Romney but indicated more unease than Graham.

“Any time you’re talking to a leader about a subject like, yeah, those are sensitive matters,” said Senate Republican Whip John Thune John Randolph ThuneHouse to vote on resolution affirming peaceful transition of power Trump dumbfounds GOP with latest unforced error Senate passes resolution reaffirming commitment to peaceful transition of power MORE (S.D.).

But Thune added that he didn’t think it would change most people’s minds or justify the House impeachment push.

Republicans in recent days have given themselves some daylight with Trump.

McConnell, the majority leader, told reporters Tuesday that he pressed Secretary of Defense Mark Esper Mark EsperOvernight Defense: Stopgap spending measure awaits Senate vote | Trump nominates former Nunes aide for intelligence community watchdog | Trump extends ban on racial discrimination training to contractors, military Overnight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Official: Pentagon has started 'prudent planning' for full Afghanistan withdrawal by May MORE and Secretary of State Mike Pompeo Michael (Mike) Richard PompeoWatchdog confirms State Dept. canceled award for journalist who criticized Trump Trump's push for win with Sudan amps up pressure on Congress Putin nominated for Nobel Peace Prize MORE over the summer about the delay in sending foreign aid to Ukraine but didn’t receive an explanation for the holdup.

Also on Tuesday, Republican leaders did not object to a sense-of-the-Senate resolution proposed by Democrats calling on Trump to release the complaint filed by an anonymous whistleblower with the intelligence community’s inspector general, Michael Atkinson.

Democrats were convinced the readout of the Trump-Zelensky call offered clear evidence that Trump abused his power to achieve personal gain.

“In this telephone conversation, the president of the United States made an extraordinary request to the president of Ukraine, to investigate Trump’s political opponent and aid President Trump’s reelection campaign,” Senate Minority Leader Charles Schumer Chuck SchumerPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' 3 reasons why Biden is misreading the politics of court packing Cruz blocks amended resolution honoring Ginsburg over language about her dying wish MORE (D-N.Y.) said. “Does anyone think this conversation was in the national interest? Or was it in the president’s personal political interest?”

Some Republicans agreed the contents of the transcript made them uncomfortable.

Sen. Rob Portman Robert (Rob) Jones PortmanMcConnell locks down key GOP votes in Supreme Court fight Romney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery MORE (R-Ohio) said he would have preferred Trump not to have discussed a prominent political rival with Zelensky but he also criticized House Democrats for launching an impeachment inquiry before knowing the contents of the transcript.

“Would it have been better if he hadn’t brought up Biden’s name? Yes, I agree with that. But the rush to judgment by the other body I think is totally unwarranted,” he said.

Collins, a top Democratic target in 2020, said the transcript “raises a number of important questions” but added that she would not draw any conclusions on Trump’s conduct at this point.

“If there are articles of impeachment I would be a juror, and as a juror I think it’s inappropriate for me to reach conclusions about evidence or to comment on the proceedings in the House,” she told reporters.

Gardner was on his phone and unavailable to comment at a vote shortly before lunchtime. His office did not respond to a request for comment.

A Republican senator who requested anonymity expressed concern that the transcript will fuel the Democrats’ fervor to impeach Trump and blow up progress on bipartisan legislation.

“I’m concerned about the transcript because I want to get nutrition assistance done,” the lawmaker said.

Other senators staunchly defended Trump.

Tillis called the House impeachment inquiry “another pathetic attempt by Democrats to destroy President Trump with falsehoods to overturn the results of the 2016 election.”

Ernst dismissed the transcript as lacking incriminating evidence.

“The fact that House Democrats dove head first into an impeachment inquiry before seeing this transcript shows exactly what we’ve known all along: They are determined to impeach President Trump. I’ve looked at the transcript; I don’t see anything there,” she said.

Sen. David Perdue (R-Ga.), who faces reelection next year, said there was “nothing” in the transcript that backed up the whistleblower’s complaint.

“I just am embarrassed, almost, that the Speaker would take this document, having not seen it, and take it to an impeachment conversation,” he said.

A moderate Democrat who spoke on condition of anonymity to The Hill said it would have been better if Pelosi had waited until after the transcript was made public but noted she was under tremendous pressure.

“I think it would have been smart to wait until she saw the transcript,” the senator said, adding, “I don’t think Speaker Pelosi had a choice.”

Jordain Carney contributed.