NEW YORK (AP) -- Former Tennessee congressman Harold Ford Jr. says he's decided not to challenge Kirsten Gillibrand for U.S. Senate in New York's Democratic primary because he doesn't want to divide the party.

Ford says in a New York Times op-ed posted online Monday he refuses to do anything that would help a Republican win the seat. He says a primary would be "highly negative."

Ford spent seven weeks traveling the state and meeting party leaders.

He was gauging support for a possible challenge to Gillibrand, who was appointed by New York's governor when Hillary Rodham Clinton became U.S. secretary of state.

Ford represented a Tennessee district in Congress for 10 years. He moved to New York City after losing a 2006 U.S. Senate race.

A Gillibrand spokesman says the senator will "wage a vigorous campaign."