Kamala Harris praised Donald Trump’s former chief of staff for sending a “911 call” to the nation about the former president’s unfitness to serve a second term, attacking her opponent as a “fascist” who would send the nation down a dangerous path.

Harris participated in a CNN town hall with undecided voters in Delaware county, Pennsylvania, on Wednesday, as the battleground state appears poised to play a potentially decisive role in the presidential race. While taking voters’ questions on everything from the cost of living to abortion access, Harris repeatedly steered the conversation back to questions over Trump’s fitness for office.

The town hall came a day after the Atlantic published a story detailing former Trump advisers’ accounts of the then president expressing a wish for “the kind of generals that Hitler had”. The article quoted Trump’s former chief of staff, John Kelly, who described the former president’s consistent pattern of demeaning members of the military. The Trump campaign has denied these accounts.

“I do believe that Donald Trump is unstable, increasingly unstable, and unfit to serve,” Harris told the CNN anchor Anderson Cooper at the town hall. “The people who know Donald Trump best, the people who worked with him in the White House … they have said explicitly he has contempt for the constitution of the United States. They have said he should never again serve as president of the United States.”

Harris predicted that, if elected to a second term, Trump would not have advisers like Kelly who might help put guardrails around the former president’s behaviour in office.

“[Kelly] is just putting out a 911 call to the American people,” Harris said. “And this time, we must take very seriously, those folks who knew him best and were career people are not going to be there to hold him back.”

When asked explicitly by Cooper whether she considered Trump to be a fascist, Harris said, “Yes, I do.”

While criticizing Trump’s character and platform, Harris sometimes sidestepped difficult policy questions from Cooper and audience members. In one of her most substantive answers of the night, Harris said she believed Democrats needed to “take a look at the filibuster” to expand abortion access in the country.

Democrats have pledged to reinstate Roe v Wade if they win the White House and regain full control of Congress, but such a proposal could be blocked by the Senate filibuster, which requires the support of at least 60 out of the chamber’s 100 members to advance bills. The filibuster became a fundamental obstacle to implementing much of Joe Biden’s legislative agenda and could present more challenges if Harris were to win the presidency.

While Harris’s openness to amending the filibuster might prove popular with the Democratic base, some of her other answers may fall short for the progressives she needs to turn out on election day. Harris reiterated her opposition to a ban on fracking and offered a somewhat muddled answer on ending the war in Gaza.

A voter, Annalise Kean, asked Harris: “What would you do to ensure not another Palestinian dies due to bombs being funded by US tax dollars?”

Harris replied: “Far too many innocent Palestinian civilians have been killed. It’s unconscionable, and we are now at a place where, with [Yahya Sinwar’s] death, I do believe we have an opportunity to end this war, bring the hostages home, bring relief to the Palestinian people and work toward a two-state solution.”

Although much of the town hall focused on criticism of Trump and policy questions, the discussion occasionally turned to the personal. Harris talked about the role of religion in her life, noting that she prays every day and spoke to her pastor the day Biden withdrew from the presidential race.

Toward the end of the town hall, Anderson asked Harris about her experience grieving her mother, who died from cancer 15 years ago.

“You don’t stop grieving,” Harris said. “It is important to try and remember them as they lived, not as they died.”

With less than two weeks left before election day, Harris and Trump appear locked in a neck-and-neck race that will come down to a handful of battleground states, including Pennsylvania. In her closing message at the town hall, Harris returned to Trump’s stability, pointing to his recent comments describing Democrats as “the enemy from within” as evidence of his unfitness to serve.

“He’s going to sit there – unstable, unhinged, plotting his revenge, plotting his retribution, creating an enemies list,” Harris said. “My list will be a list of how I address and continue to address the issues that you all are raising this afternoon and evening. It will be a to-do list about how we can impact the American people.”