Meanwhile, Barnburners convened in Utica, New York on June 22; they were joined by a smaller number of Whigs and Democrats from outside New York. Though initially reluctant to accept to run for president, former President Van Buren accepted the group's presidential nomination. Van Buren endorsed the position that slavery should be excluded from the territories acquired from Mexico, further declaring his belief that slavery was inconsistent with the "principles of the Revolution". Because Van Buren had favored the gag rule and had generally accommodated pro-slavery leaders during his presidency, many Liberty Party leaders and anti-slavery Whigs were unconvinced as to the sincerity of Van Buren's anti-slavery beliefs. Historian A. James Reichley writes that, while resentment stemming from his defeat at the 1844 Democratic National Convention may have played a role in his candidacy, Van Buren ran on the grounds that "the long-term welfare of Democratic Party, and the nation, required that the Party shed its Calhounite influence, even at the cost of losing an election or two."