EAST MEADOW, N.Y. (AP) A once rising star in the Democratic Party said Thursday he had been chastened by an upset loss for a re-election in 2009 and vowed not to run for higher office if his comeback succeeds in November.

"Been there, done that," Thomas Suozzi told reporters on Thursday, two days after winning the Democratic primary for county executive in suburban Nassau County, turning back a challenge from a well-financed, but politically inexperienced Long Island businessman.

"I'm 100 percent committed to Nassau County," Suozzi said of his attempt to oust Republican Edward Mangano and get his old job back. "I will serve my entire four year term. I'm not running for any higher office."

Suozzi was beaten by Eliot Spitzer in the 2006 Democratic primary for governor and had been widely viewed as a politician with aspirations beyond Long Island.

Evidence of that was seen in 2009, when he left more than $1 million unspent in his losing re-election bid for county executive.

Suozzi admitted Thursday that he had taken his re-election bid too lightly in 2009, losing to the little-known Republican county legislator who swept into office amid the growing anti-tax Tea Party sentiment that was percolating four years ago across the country. Mangano's margin of victory was less than 400 votes.

Mangano is running for a second term, again touting his tax-cutting policies, as well as his experience handling the aftermath of Superstorm Sandy and his success in putting together a proposal to renovate the Nassau Veterans Memorial Coliseum.

Mangano spokesman Brian Nevin said after Suozi's primary victory on Tuesday night that the Republican was looking "forward to debating Suozzi's record of hiking property taxes by 23 percent and leaving behind $3.45 billion in debt."

The wealthy county just east of New York City has been under a state-imposed financial watchdog since 1999, but in 2011, it declared a fiscal emergency and imposed a wage freeze on county workers that still remains in effect.

Lawrence Levy, executive dean of the Hofstra University National Center for Suburban Studies, said this year's election in Nassau County will be watched beyond Long Island.

"Political scientists and operatives are watching races like the Nassau County Executive to see if they can glean anything that will tell them what may happen in 2014," Levy said. "One thing is certain: Tom Suozzi is not going to leave one penny in the bank, or leave any door un-knocked, or any church or synagogue unvisited. He's learned his lesson."

In other primary results Tuesday, Suffolk County District Attorney Thomas Spota won a Republican primary, virtually guaranteeing himself a fourth term; he already has the Democratic Party nomination.