Her rounding on Al Franken only served to reinforce doubts among those who have not been convinced by Ms Gillibrand’s leftward drift.
While she maintains that her earlier views reflected those of her voters in a conservative district, cynics suggest she has been burnishing her radical credentials to boost her chances of securing the nomination.
Her move to the left reflects the direction of traffic among grassroots Democrats, but some experts believe that the New York Senator will have a tough job winning the support of the party’s rank and file.
“Gillibrand’s problem is that she needs to work on her ‘conversion’ story which has seen her evolve from being a moderate Democrat from upstate New York to an unrelenting opponent of Donald Trump,” said Brandon Barford, a partner at Beacon Policy Advisors, a Washington DC-based consultancy.
“The left would say she has a ton to answer for, as they are not forgiving of ideological impurity.
“All of the candidates so far have that problem to a certain extent but Gillibrand more than most.”
Nevertheless, the 52-year-old Senator can also point to a record of solid achievement as a legislator.
She has been praised for her role in sponsoring bipartisan legislation prolonging the compensation fund for the survivors of 9/11, including first responders and workers, who contracted cancer linked to the terror attacks. It had been due to expire.
Ms Gillibrand comes from a family rooted in the politics of upstate New York. Her grandmother, Dorothea “Polly” Noonan, founded the Albany Democratic Women’s Club and was a key ally of Albany’s powerful mayor Erastus Corning.
Her father, Douglas Rutnik, was a lawyer and political lobbyist.
Privately educated, she graduated from Dartmouth College with a degree in Asian Studies. She subsequently became a lawyer, taking on pro bono cases including support to abused women and to tenants living in unsafe housing.
In 2001 she married British venture capitalist Jonathan Gillibrand, whom she met on a blind date. They have two sons, Henry and Theodore.