KEENE, N.H. — Senator Elizabeth Warren’s message on impeachment was blunt and brief. On a college campus here, Ms. Warren reminded a crowd of hundreds that she had called for President Trump’s impeachment last spring, after the release of Robert S. Mueller III’s report on Russian interference in the 2016 election. Taking action against Mr. Trump, she said then, was “a matter of constitutional responsibility.”
“If Congress does not hold this man accountable, then he will break the law again and again and again,” Ms. Warren said Wednesday. “It is time for impeachment now.”
She said she was pleased the House of Representatives had “stepped up” and expressed hope the process would move “quickly.”
And then, less than three minutes after she began speaking, Ms. Warren turned away from the subject.
Ms. Warren was not the only Democrat on Wednesday to attempt such a balancing act, as other candidates blended urgent denunciations of Mr. Trump with broader arguments for their own campaigns. Across the Democratic field, candidates are approaching the impeachment battle stirring in Washington as a matter to be addressed but also contained — a necessary process, but perhaps not one that ought to redefine their own campaigns.
Senator Bernie Sanders of Vermont released a statement labeling Mr. Trump’s “self-dealing and corruption” as “limitless,” and praising the House for formally opening an impeachment inquiry. But he also tweeted about homelessness and outsourced jobs after walking on a picket line in Michigan.
Senator Kamala Harris of California said in interview that she was shocked by the summary of a phone call the president made to the leader of Ukraine in which he urged his counterpart to investigate one of his political rivals, Joseph R. Biden Jr. But she also said her candidacy would remain focused on the scope of Mr. Trump’s presidency and not a single episode or the impeachment question narrowly.
And Mr. Biden, who held no public events on Wednesday, issued his own statement saying he would be focused “not on how Donald Trump abused his power to come after my family, but on how he has turned his back on America’s families.”
Candidates like Ms. Warren may have the stature to communicate with voters over the din of impeachment. She has risen rapidly in the polls in recent weeks, threatening to overtake Mr. Biden as the front-runner for the Democratic nomination. Ms. Warren was the first of the major Democratic candidates to demand Mr. Trump’s impeachment, but mentions Mr. Trump sparingly in her speeches. Even she is declining to transform her campaign into a crusade for his ouster.
Democratic voters, too, appear not to be focused with singular intensity on impeachment: Ms. Warren’s rhetoric on the matter drew loud applause, but no louder than the crowd’s reaction to her arguments about climate change, racial inequality and government corruption.
Among the people in Ms. Warren’s audience, there was a sense of outrage about Mr. Trump’s conduct and a sense of support for the steps taken this week by House Democrats to investigate him more aggressively.
But there was little optimism that Mr. Trump might ultimately be removed from office, and some expressed anxiety at the unpredictability of the impeachment process.
Tim Butterworth, a retired teacher who is supporting Ms. Warren, said he believed the House had a duty to proceed with impeachment even though there was “kind of a stone wall” waiting in the Republican-controlled Senate. Mr. Butterworth did not mention Ms. Warren’s support for impeachment among his reasons for supporting her, focusing instead on her plans for addressing economic inequality.
“I think it would be easier to defeat him in an election,” Mr. Butterworth, 75, said of the president. “But when you see a crime being committed, you have to report it. If you don’t, you’re complicit.”
Ellen Moran, an undecided voter who works in urgent care, expressed both exasperation with Mr. Trump and some trepidation about impeachment. Ms. Moran, who is deciding between Ms. Warren and Pete Buttigieg, the mayor of South Bend, Ind., said it was “embarrassing, frankly, as an American that we have to come down to this.”
Earlier in the day, Ms. Warren was one of at least two candidates, along with the former housing secretary Julián Castro, who labeled the reconstruction of the phone call a “smoking gun.”
The call between Mr. Trump and President Volodymyr Zelensky of Ukraine is at the center of accusations that Mr. Trump pressured a foreign leader to open a potential corruption investigation tied to Mr. Biden, who is seeking to challenge Mr. Trump in 2020.
The news of the call — which was first revealed by a whistle-blower who works in the intelligence community — prompted House Democrats to say on Tuesday they would formally open an impeachment inquiry.
The rapid developments in Washington provided a rare chance for most of the 19 Democratic candidates to offer a unified response in a primary that has increasingly seen them draw distinctions with each other in an attempt to stand out.
The near-uniform embrace of an impeachment inquiry represents a significant shift from this spring, after the release of the report by the special counsel, Mr. Mueller, on Russian interference in the 2016 election, when fewer candidates explicitly endorsed beginning an impeachment inquiry.
Poll after poll has shown that Democratic voters’ top priority is beating Mr. Trump in the 2020 general election, and the allegations that he pressured a foreign leader in an effort to hurt a political rival have enabled the candidates to collectively paint him as unfit to occupy the presidency.
In the interview, Ms. Harris said the time for impeachment had come. “This guy has told us who he is,” she said. “He believes he’s above the law. And everything that has happened in these years continues to tell us that.”
Her campaign on Wednesday also highlighted the role of Attorney General William P. Barr in the various controversies surrounding Mr. Trump. Ms. Harris’s communications director resurfaced an exchange between Ms. Harris and Mr. Barr during a Senate Judiciary Committee hearing in May about Mr. Mueller’s report, in which she asked the attorney general whether Mr. Trump had ever asked him to open an investigation into anyone else. After much hesitation, Mr. Barr said he did not know.
In the interview, Ms. Harris, a former prosecutor who ran California’s Department of Justice, raised concerns about the fact that Mr. Trump had urged Mr. Zelensky to contact Mr. Barr about opening an investigation.
“Is he using his power in a way that’s for political advantage rather than the pursuit of justice?” Ms. Harris asked. “Yes, I have a question about where is this attorney general’s loyalty, and to whom, and to what end.”
Not every candidate in the Democratic primary supports an impeachment inquiry. Representative Tulsi Gabbard, who has long opposed that remedy, argued Tuesday on Fox News that “impeachment at this juncture would be terribly divisive for the country.”
And on Wednesday, she said that seeing the reconstructed transcript had not changed her mind. “Most people reading through that transcript are not going to find that extremely compelling cause to throw out a president,” she said.
Most of the rest of the Democratic candidates however were unequivocal in their calls for an impeachment investigation to begin.
Senator Cory Booker of New Jersey said that the memo on the phone call was “apparent proof that Trump had pressured a foreign nation to meddle in our democracy again.”
“History will remember those who put politics aside at this time of crisis and treated it like the moral moment that it is,” he said.
Senator Amy Klobuchar of Minnesota said that the record of the call was “deeply disturbing,” adding that Mr. Trump had “violated the public’s trust.”
“It’s shameful,” she said. “Our country deserves better.”
And Mr. Castro, in an interview, called Mr. Trump’s conduct “egregious.”
“I want to see Donald Trump held accountable and for the House to move forward with impeachment,” he said.
Astead W. Herndon contributed reporting from New York and Jennifer Medina contributed reporting from Oakland, Calif.