The independent expenditure committee backed by the New York State United Teachers union is starting a $653,000 ad blitz in two key state Senate races in central New York and on Long Island, according filings Wednesday at the state Board of Elections.

The union’s Fighting For Our Future committee is spending $210,000 on a TV ad in the district of Sen. Carl Marcellino, the chairman of the Senate Education Committee. At the same time, the union is spending $47,466 on a mailer in the Long Island district.

Marcellino this year faces a rematch against Democrat Jim Gaughran.

In the Syracuse area, the committee $270,000 on a TV ad in support of Democrat John Mannion, a former president of the local teachers union, as well as a $50,000 purchase for a digital ad. The group is also spending an additional $75,000 on mailers in the district.

Mannion is running for the seat held by retiring Sen. John DeFrancisco, a Republican. Onondaga County Comptroller Bob Antonacci is seeking to hold the seat for the GOP.

NYSUT’s heavy spending on key Senate races comes after the GOP conference this year did not pass legislation that would have decoupled teacher evaluations from the results of standardized tests. The bill had been pushed by NYSUT in the final months of the legislative session and the failure to gain a vote had upset the union.