WASHINGTON -- Rep. Allyson Schwartz (D-Pa.) resigned as honorary co-chair of the centrist group Third Way on Thursday, in part because of a December op-ed written by the group's real leaders declaring that embracing economic populism would be "disastrous" for Democrats. Schwartz seeks to challenge Pennsylvania Gov. Tom Corbett (R) in this year's gubernatorial election.

"As the May primary approaches, I had long planned to step aside from other commitments. As such, I am ending my leadership role with New Democratic Coalition, honorary role with Third Way and service on [the] House Budget Committee -- to keep my focus serving the people of the 13th Congressional District, winning this campaign for governor, and finally getting Pennsylvania back on track," she said in a statement to HuffPost. Her spokesman, Mark Bergman, said it was correct that the Third Way op-ed made that decision "easier."

The liberal blog Daily Kos first reported the news.

The Progressive Change Campaign Committee, Progressives United and Democracy For America had all pressured Schwartz in December to resign her honorary position at Third Way. At the time, her spokesman said the congresswoman thought that the op-ed was "outrageous and strongly disagree[d] with it."

Schwartz is the first Democratic lawmaker to resign from the group in the wake of the op-ed, which slammed calls to expand Social Security and criticized Sen. Elizabeth Warren (D-Mass.) and New York City Mayor Bill de Blasio (D). Other Democrats have denounced the op-ed, but no one else said he or she would resign from the group.