The Working Families Party on Wednesday will announce its endorsement of Democratic state Senate hopeful John Liu in his bid to unseat Sen. Tony Avella in the Sept. 13 primary.

“In the City Council and as Comptroller, John Liu has consistently championed working families—and we know he’ll be a progressive leader in New York’s State Senate,” said Bill Lipton, Director of the Working Families Party of New York. “For far too long, Tony Avella betrayed his constituents and sided with the Republican Party. Enough is enough. John will stand up for small businesses owners, immigrants, students and women, and the WFP is proud to endorse him for State Senate.”

This is Liu’s second attempt at unseating Avella in his Queens district. Avella is a former member of the Independent Democratic Conference, which dissolved in April and rejoined the mainline fold.

But Avella, like several former IDC lawmakers, continue to face primary challenges fueled in large part by their membership in the conference. The WFP in particular has sought to back candidates against former IDC senators.

“The Working Families Party and I stand for the same set of values that protect and nurture New York’s working families,” Liu said in a statement. “I am proud to receive their endorsement and I will continue to champion progressive policies as a true Democrat in Senate District 11.”