Former New York City Mayor Rudy Giuliani (R) said that his state's next senator should be able to stand up for Gotham.

"When New York City is functioning well, the entire economy is functioning well," Giuliani wrote in an op-ed on

"As we see today, when the city's financial industry is not functioning well, the entire country struggles," he added. "As the nation's biggest city, New York City needs an advocate with the toughness to fight for everything to which we are entitled."

Giuliani said that the state's past four senators, Daniel Patrick Moynihan (D), Alfonse D'Amato (R), Charles SchumerCharles (Chuck) Ellis Schumer2020 Republicans accuse Schumer of snubbing legislation Schumer: Leadership trying to work out competing surprise medical bill measures Top GOP senator: Drug pricing action unlikely before end of year MORE (D) and Hillary Rodham Clinton (D), have all been effective advocates.

"Each understood the crucial role that New York City plays in New York's economy and in America's economy, as the place that develops the capital that makes the economy work -- the heart that pumps the blood, so to speak," Giuliani wrote.

One of the state's two Senate seats will be open once Clinton is confirmed as secretary of State. Clinton's successor will be appointed by Gov. David Paterson (D-N.Y.). The seat will be up for election in 2010.

Giuliani, who briefly ran for Senate in 2000, has little interest in running for Senate in two years, according to Rep. Peter King (R-N.Y.), who plans to run for the seat himself. Giuliani has been mentioned as a possible gubernatorial candidate.