JD Vance offered an unusually affectionate description of himself on the campaign trail this week, insisting he was a "sweetheart" before acknowledging that some people see him rather differently.

Speaking at a Republican rally in Rome, New York, on November 2, the US vice president joked about his reputation for taking an aggressive approach to political opponents. "I'm really a sweetheart," he told supporters, before adding that "some people say that I'm an attack dog."

But the remarks were more than a passing joke about his personality. They came during a campaign appearance supporting Republican congressional candidate Anthony Constantino, who was challenging Democrat Blake Gendebien in New York's 21st Congressional District.

According to the full transcript of Vance's speech, the vice president quickly moved from his light-hearted self-description to attacking Constantino's opponent, accusing Gendebien of showing contempt for American workers.

That shift helps explain the joke. Vance was contrasting the friendly image he claimed for himself with the combative political role he was performing in front of Republican supporters.

Interestingly, the New York appearance was not the only time Vance used that contrast on November 2.

At another campaign rally in Swanton, Ohio, the vice president again addressed his reputation as an attack dog, this time describing himself as "nice and cuddly" before turning his attention to Democratic Senate candidate Sherrod Brown.

The Ohio speech transcript shows Vance making a similar transition from joking about his temperament to criticising a political rival.

The repetition provides context missing from the isolated New York clip. Rather than a spontaneous confession about his personality, the remarks formed part of a recurring campaign message in which Vance used humour to introduce attacks on Democratic candidates.

Both appearances took place on the final day before the November 3 midterm elections, as Vance travelled to support Republican candidates and encourage supporters to vote.

Whether audiences consider him a sweetheart or an attack dog is a matter of opinion. What the two speeches establish is that Vance was comfortable playing both roles on the campaign trail, sometimes within the same sentence.