With the midterm elections still 10 months away, political tensions are already flaring in one of Long Island’s most closely watched congressional districts.

An attack advertisement targeting Democratic Rep. Laura Gillen will air in Nassau County’s 4th Congressional District, underscoring the seat’s importance in the national battle for control of the U.S. House of Representatives.

The ad, paid for by the National Republican Congressional Committee (NRCC), accuses Gillen of taking credit for $1 million in funding to purchase a new firetruck for Bellerose Village despite voting against the legislation that approved the money. The spot claims Gillen “gambled with New Yorkers’ lives” by opposing the bill.

NRCC spokesperson Maureen O’Toole criticized Gillen for holding an event celebrating the funding. “This is funding that she voted against and she’s trying to take credit?” O’Toole said.

Gillen rejected the accusation. She said she worked for nearly a year to secure the funding for the firetruck but ultimately voted against the final bill because it was tied to broader legislation that allowed Affordable Care Act subsidies to lapse, a provision she and most Democrats opposed. “It was regrettable that the Washington Republicans tried to politicize this clean funding bill by attaching it to a bill that would rip healthcare away from millions of Americans,” Gillen said.

The early advertising blitz highlights the significance of New York’s 4th District, which has changed party control several times in recent election cycles. Political analysts say the district is likely to be one of the more heavily contested races in the country.

“The majority in the House is razor thin,” said Mike Dawidziak, of Strategic Planning Systems. “When you get a swing district like this, it’s going to get a lot of attention and a lot of money poured into it.”