Republican Kevin Faulconer was elected the next mayor of San Diego on Tuesday, emerging from a competitive and expensive runoff election against a Democratic opponent who had strong support from organized labor and the endorsement of President Obama.

Kvvin Faulconer (R), left. (Lenny Ignelzi/AP)
Kvvin Faulconer (R), left. (Lenny Ignelzi/AP)

San Diego will become the largest American city with a Republican mayor. Faulconer, a city councilman, defeated Democratic City Councilman David Alvarez, 55 percent to 45 percent.

Alvarez conceded to Faulconer late Tuesday, tweeting, "I want to congratulate Kevin Faulconer. It's clear that he will be the next Mayor of San Diego. I look forward to working with him."

Faulconer responded: "Thank you for a respectful campaign. As mayor, I look forward to working with you to move our city forward."

Faulconer will fill out the remainder of Democrat Bob Filner's term. Filner resigned in disgrace last year amid mounting sexual harassment allegations. He was San Diego's first Democratic mayor in two decades.

Labor unions spent seven figures trying to elect Alvarez. He even got an eleventh-hour endorsement from Obama. But ultimately, the backing of the president would prove no match for Faulconer's moderate Republican pitch.