One of most closely-watched races in New York is on Long Island, in the 2nd Congressional district.

Democrat Jackie Gordon is running against Republican Andrew Garbarino. 

Republican Congressman Peter King has held the seat for more than a quarter of a century, and he's retiring at the end of the year. But recent demographic shifts have turned the district more blue, and a Democratic victory there could help solidify the party's majority in the House of Representatives. 

Newsday political reporter Scott Eidler says there's a lot at stake for both parties. New York Republicans are concerned the Democratic-led state legislature could re-draw the district to become more blue in coming years. Having a Republican incumbent in the seat could help the party in the next election, in 2022. 

"This is a big deal for Republicans to try to preserve their power on Long  Island and in New York," Eidler said. 

Listen to his conversation with WNYC's Kerry Nolan, above.