SAN FRANCISCO >> The Oakland A’s yearslong quest for a new home is really a tale of three cities.

Oakland is desperately trying to keep the team from moving out of a city already struggling with crime, financial woes and blow after blow to its public image. Mayor Jean Quan has made retention of the A’s a focal point of her re-election campaign.

To the south in the heart of booming Silicon Valley, San Jose is seeking to bolster its profile and treasury with an aggressive campaign to win the A’s, including a legal challenge to Major League Baseball’s sacrosanct antitrust exemption that the mayor vows to take to the U.S. Supreme Court if necessary.

Standing in the way are San Francisco’s Giants, who claim the lucrative Silicon Valley commercial market as their exclusive territory. And so far, the Giants are winning.

On Nov. 25, the A’s announced the signing of a two-year lease to play in O.co Coliseum through the 2015 season. And recently filed court documents revealed that MLB Commissioner Bud Selig informed the A’s this summer that the league had rejected the team’s proposed move to San Jose.

On a hearing on Dec. 13, U.S. District Court Judge Ronald Whyte in San Jose asked MLB lawyer John Keker if the letter was an “unequivocal” denial.

“What the A’s asked the commissioner to approve was unequivocally denied,” Keker replied.

Baseball’s antitrust exemption — granted by Congress and confirmed by the U.S. Supreme Court — has allowed the league to operate for nearly a century as an otherwise illegal monopoly that enjoys tight control over its member clubs.

Selig’s letter itself wasn’t included in the court filing and no reason was disclosed for the league’s rejection of the A’s proposed move — though San Jose strongly suspects the league is acquiescing to the Giants commercial interests.

The commissioner’s letter does not preclude the A’s ownership from resubmitting a new application for a move to San Jose. And the A’s still want to move from the coliseum because of its state of disrepair and the fact that it shares the stadium — and revenues — with the Oakland Raiders of the NFL.

In September, A’s players reported foul smells from the bathroom end of their dugout. That came after a June incident in which a clogged pipe caused a sewage backup and flooding on the bottom floor of the ballpark that sent the Seattle Mariners and A’s scrambling around in towels and heading for higher ground in the Raiders’ locker room.

After a hazmat crew inspected the affected areas, new carpeting was installed; other extensive repairs were made to the visiting clubhouse.

Calling the coliseum “a pit,” Selig has acknowledged the A’s need a new stadium, but has stopped short of naming or advocating a location.

Historically, landing professional teams has done little to improve the winning city’s bottom line, said Nathaniel Grow, a University of Georgia law school professor and expert in the field of sports business.

“The economics are usually overstated,” Grow said. “But there is an intangible civic pride element that national exposure brings with professional sports teams.”

Nonetheless, San Jose and Oakland want the A’s.

“If it wasn’t for the Giants, the A’s would be playing in San Jose,” said San Jose Mayor Chuck Reed, who figures the A’s will generate $5 million in tax revenues annually while bolstering the city’s civic pride. “It certainly would have a dramatic impact on our downtown.”

The Giants have declined to discuss their role in the A’s proposed move to San Jose. But MLB says the city is part of the Giants’ marketing territory, which the league is able to protect through an antitrust exemption granted by Congress and upheld by the U.S. Supreme Court in 1922.

The court has upheld the antitrust exemption two more times, the last in 1972.

Numerous lower federal courts, citing the Supreme Court rulings, have also declined to disturb the antitrust exemption as applied to player contracts, MLB’s move into cities with minor league teams, the league’s “franchise location system” and other areas of MLB’s business interest.

During San Jose’s five-year pursuit of the A’s, the team’s owners have been receptive. A’s Managing Partner Lew Wolff has paid $100,000 for an option to buy six parcels of land in downtown San Jose from the city for $7 million to build a stadium near the home of the NHL’s San Jose Sharks.

But frustrated with MLB’s apparent inaction on the A’s proposal to move to Silicon Valley, San Jose filed a federal lawsuit on June 18 seeking to invalidate the antitrust exemption and pave the way for the A’s to move there.

Judge Whyte rejected San Jose’s antitrust claims and allowed the city to pursue an expedited appeal to the 9th U.S. Circuit Court of Appeals — one rung below the U.S. Supreme Court — while ordering its claims of contract interference to be decided in state court.

Meantime, Oakland’s mayor is not letting the A’s leave without a fight. Quan said the city has at least two sites the A’s can use to build a new stadium or the current stadium can be repaired and remodeled to the A’s satisfaction. Quan said she believes the A’s will have difficulty moving to San Jose because of the Giants’ territorial rights.

“The odds of them leaving have never been particularly good,” she said.