She's made a public series of explanations. She told CBS' "60 Minutes" last year she was "embarrassed" by her previous views on guns. Last month, she went on MSNBC's "Rachel Maddow Show," a must-stop for Democratic presidential candidates, and explained her shift.
"I recognized I didn't know everything about the whole state," Gillibrand said.
Last week, Gillibrand took her image-building to a more intimate setting, a house party in Portsmouth, N.H. About 25 people were there, including many Democratic officials from what's traditionally the nation's first primary state. People asked about issues, but were most interested in getting a sense of her authenticity.
"I asked about her value system," said Laurie McCray, Portsmouth Democratic chairwoman.
Gillibrand brought up her views on guns, explaining how she had grown up in a culture where guns were routinely used.
She mentioned her role in the Al Franken controversy. Gillibrand was the first senator to call on Franken, a Minnesota senator, to resign after photos surfaced showing him groping a woman.
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A lot of Democratic colleagues weren't pleased that Franken, respected for his work on party issues, was pressured. Gillibrand discussed her work on strengthening laws against sexual assaults, a constant theme in her Twitter feed.
What lingered after the evening was that "she was passionate about the issues she cares about," said Larry Drake, Rockingham County Democratic chairman.
Gillibrand followed a familiar script: Go public in friendly forums, building a reputation as a devoted fighter for certain issues, then gently take the time to explain to the activists who are influential in these early campaign stages that you're sincere. Her campaign did not respond to a request for comment.
The danger for a candidate lurks if a past position or stumble is too raw to overcome, or it feeds an already-lingering widespread doubt, said Kyle Kondik, managing editor of Sabato's Crystal Ball at the University of Virginia.