Representative Tulsi Gabbard of Hawaii endorsed the impeachment inquiry against President Trump on Friday, dropping longstanding opposition that she had affirmed as recently as two days ago.
Her announcement means the 19 Democratic presidential candidates unanimously support the inquiry. Ms. Gabbard had been the only holdout after the White House released a reconstruction of a July phone call in which Mr. Trump urged the president of Ukraine to investigate former Vice President Joseph R. Biden Jr. and his son.
“Up to this point, I have been opposed to pursuing impeachment because it will further divide our already badly divided country,” Ms. Gabbard said in a statement from her congressional office. “However, after looking carefully at the transcript of the conversation with Ukraine’s president, the whistle-blower complaint, the inspector general memo and President Trump’s comments about the issue, unfortunately, I believe that if we do not proceed with the inquiry, it will set a very dangerous precedent.”
She added: “If we allow the president to abuse his or her power, then our society will rot from top to bottom. We will turn into a banana republic, where people in positions of power — from the president all the way down to the traffic cop — will feel it’s O.K. to abuse their power with no consequences.”
As one of two sitting representatives still in the race (the other is Tim Ryan of Ohio), Ms. Gabbard will be able to cast a vote if, in fact, articles of impeachment are sent to the House floor.
What effect, if any, impeachment proceedings will have on the presidential race itself is impossible to say. Ms. Gabbard’s previous opposition to impeachment made her a loner in the Democratic field, but that was not unusual: She has stood apart from the rest of the candidates on a variety of issues, especially foreign policy.
The announcement on Friday was a remarkable turnaround for Ms. Gabbard, who had said just two days ago that she did not think the reconstructed call had shown “compelling cause” for impeachment. In an interview with Hill TV on Wednesday, when asked directly whether the transcript had changed her thinking on impeachment, she said, “It hasn’t.”
“I’m not a lawyer, but I think most people reading through that transcript are not going to find that extremely compelling cause to throw out a president that won an election in 2016,” she said then. “Instead, what I think most people will see is, ‘Hey, this is another move by Democrats to get rid of Donald Trump,’ further deepening the already hyperpartisan divides that we have in this country.”
A spokesman for her office provided the statement on Friday but did not immediately respond to a question about what had caused Ms. Gabbard to change her mind.
The whistle-blower complaint, released on Thursday, at the center of the inquiry included new allegations that the White House had tried to cover up the phone call by putting the transcript in a computer system intended for highly classified information.
While the Democratic presidential field is now united in support of the impeachment inquiry that Speaker Nancy Pelosi announced on Tuesday, the candidates, like the congressional Democratic caucus, are still divided on how extensive the inquiry should be. It is an open question, for example, whether articles of impeachment — if the inquiry leads to them — should focus only on the Ukraine issue or also include past actions by Mr. Trump.
Ms. Gabbard argued that the inquiry should be “swift, thorough and narrowly focused.”
“It cannot be turned into a long, protracted partisan circus that will further divide our country and undermine our democracy,” she said.
Ms. Gabbard is still a long-shot candidate for the Democratic nomination, consistently polling in the low single digits in voter surveys. But this week, she hit a polling threshold that qualified her for the next debate in October.