Zephyr Teachout did not get the Working Families Party’s ballot line in May.

But now the WFP and Teachout, who went on to challenge Gov. Andrew Cuomo for the Democratic Party’s nomination in September, are joining forces to oppose the anticipated effort to expand charter schools next year.

“We refuse to let the forces that bought our elections transform our public education system,” said WFP Director Bill Lipton in a statement. “Zephyr Teachout is a force to be reckoned with and we’re proud to launch this fight with her for quality education for every student.”

Both Teachout and WFP members appeared in New York City outside of the Tweed Courthouse on Tuesday, launching an anti-charter school campaign and knocking the hedge-fund managers backing the effort.

The labor-backed ballot line and Cuomo have been at odds since the summer despite having a temporary truce in May, when the governor pledged to support the WFP’s agenda such as the Dream Act, a steeper increase in the minimum wage and allowing local governments to increase the wage on their own.

Though the WFP backed Cuomo, the governor formed his own ballot line this fall, the Women’s Equality Party, that some advocates blame for siphoning votes away from the liberally minded party.

The WFP will fall a notch on the ballot after the Green Party’s Howie Hawkins outperformed Cuomo on the WFP ballot line last month.

Teachout, who campaigned on her opposition to hydrofracking and backing of public financing, proved to be more than a passing irritant for Cuomo.

She received about 35 percent of the vote against Cuomo, a better-than-expected showing for a relatively unknown candidate.

Cuomo himself is a booster of charter schools in New York and has criticized public education as a “public monopoly” he wants to curtail.

The governor has been supported by charter school advocates, which have also contributed heavily to super PACs that backed Republican state Senate candidates.

Update:Jenny Sedlis, of education reform group StudentsFirstNY, responded in a statement.

“After spending more than $8 million on this year’s elections alone, it is the height of audacity for the special interests that created our broken education system to attack civic-minded individuals who are standing up for students. The teachers’ unions have been spreading around millions in campaign cash for years — all to protect the financial interests of their members at the expense of the educational needs of our children, especially the most vulnerable of them. Unlike the forces of the status quo, our supporters have no personal stake in this debate other than improving the quality of public education for all students in New York State.”