CEDAR RAPIDS, Iowa — Sen. Elizabeth Warren (D-Mass.) told voters Sunday that President Trump might be unable to finish his term, firing back at him for the first time since his reelection campaign attacked her rollout.

“By the time we get to 2020, Donald Trump may not be president,” Warren told an audience here. “In fact, he may not even be a free person.”

Warren had not previously hinted that the scandals surrounding the president could keep him from seeking a second term. On her previous trip to Iowa, she rarely mentioned Trump by name.

But her campaign, which has faced more direct attacks from Trump than other Democratic candidates, appears to see the question about Trump’s own viability as way to stop engaging with everything he says.

Asked to expand on her comments later in the day, Warren quipped: “Come on, how many investigations are there now? It’s no longer just the Mueller investigation, they’re everywhere. And these are serious investigations.”

Warren also sought to put her comments in a broader context, explaining that she doesn’t often mention Trump at events because her campaign is more than just ousting the Republican president.

“Things were broken long before Donald Trump got here,” Warren said, speaking to reporters after a rally that drew about 500 people in Iowa City. “He made a whole lot of things a whole lot worse.” But she said simply saying “‘not Trump’ then we’re not going to make the changes that this country really needs.”

Warren formally kicked off her bid for the 2020 Democratic presidential nomination before a crowd of about 3,500 supporters in Massachusetts on Saturday. She is part of a rapidly expanding Democratic White House field that includes Sens. Kamala D. Harris (Calif.), Cory Booker (N.J.) and Kirsten Gillibrand (N.Y.).

Sen. Amy Klobuchar (D-Minn.) is expected to announce her bid Sunday afternoon, and Sen. Michael F. Bennet (D-Colo.) hinted in a Sunday morning interview on NBC’s “Meet the Press” that he, too, may pursue a run.

Warren’s remark comes as Trump’s legal woes mount and as special counsel Robert S. Mueller III’s investigation on Russian election interference has closed in on several key members of the president’s orbit.

A little more than halfway into his first term, nearly every organization Trump has led over the past decade is under investigation. The challenges include civil suits against Trump’s private company and charity, as well as several looming investigations by House Democrats.

With last month’s indictment of Roger Stone, Trump’s longtime friend and adviser, 34 people have been charged in the Mueller investigation, and six Trump associates have pleaded guilty.

Trump has repeatedly dismissed the Mueller probe as a “witch hunt,” and in his State of the Union address on Tuesday, he claimed “ridiculous partisan investigations” could hurt the country’s prosperity.

“If there is going to be peace and legislation, there cannot be war and investigation,” Trump said.

The idea that scandals might force Trump from office is widespread among Democratic voters, and other candidates have hinted at it, too.

“Impeachment, prison, not reelected, runs off and hides on a Caribbean island — I don’t care,” said Andrea Taylor, a 44-year-old respiratory therapist in Cedar Rapids. “I just don’t want him to keep hurting our country.”

At a Saturday morning town hall in Marshalltown, Iowa, Booker had an exchange with a voter who said she wanted a candidate tough enough to beat Trump. The New Jersey Democrat replied that he was ready for the fight — but that he was unsure whether the president would be on the ballot.

“Should I be our nominee and Trump also be their nominee — I’m not sure that he will be — you will see the toughest person standing against him,” Booker said.

Annie Linskey in Iowa City, Iowa, contributed to this report. Sonmez reported from Washington.