Seattle officials filed a lawsuit today in King County Superior Court in an attempt to force the Sonics to continue playing at KeyArena through 2010.

Seattle City Attorney Tom Carr announced the lawsuit at a morning press conference with former U.S. Sen. Slade Gorton, whose law firm has been hired by the city for the lease dispute.

"Too often pro sports teams have run over local governments and gotten their way with them. Today we are standing up and saying 'no.' We have an agreement. We are going to enforce that agreement. We want you to honor your promises," Carr said.

Gorton said the city's lawsuit was triggered by Sonics' owner Clay Bennett's demand last week for arbitration to get out of the final two years of the Sonics' lease at KeyArena.

The city's lawsuit seeks to block the Sonics' attempt to move the lease fight to arbitration, a legal tactic team owners announced on Friday. The suit also seeks a court order stating the city can hold the team to its KeyArena lease through 2010. In addition, the city wants the Sonics to pay its legal fees.

Gorton slammed the actions of Bennett's Oklahoma City-based ownership group, which purchased the team last year for $350 million.

"Regrettably, almost from the beginning those Oklahoma owners gave every indication that they did not intend a longtime stay in the city of Seattle," Gorton said, citing recent comments from part-owner Aubrey McClendon that the new owners never wanted to keep the Sonics in Seattle despite their public statements.

Gorton called the owners' efforts to get a $500 million arena built in Renton "the kinds of demands that from my perspective were almost designed not to be met."

The city's lawsuit argues that KeyArena was built for the Sonics only on the condition that the team sign and honor a 15-year lease and that a cash settlement would not be adequate compensation if the team were to leave early.

The suit argues that the Sonics' recent financial woes have more to do with the team's spate of losing seasons than with KeyArena.

"The issues with the Sonics profitability at KeyArena have less to do with KeyArena than perhaps the Sonics' ability to defend the high pick & roll," Carr said. "Good teams, competitive teams have done well here."

Bennett said last week he wants a panel of impartial arbitrators to "bring some clarity" to the lease — specifically on the question of whether the Sonics simply can pay a cash settlement to leave before the lease expires in 2010. The Sonics' arbitration filing blames KeyArena for losses of $17 million last year.

Bennett said his arbitration demand, filed by the Seattle law firm Byrnes & Keller, was a response to increasingly hostile statements by Seattle officials, who have vowed to bind the Sonics to KeyArena until the team's lease ends in September 2010. He cited Seattle Deputy Mayor Tim Ceis' recent comment that the city was "lawyering up" by enlisting Gorton to help enforce the lease.

Bennett, who could not be immediately reached this afternoon, has said that even a renovated KeyArena "is a dead end."

Jim Brunner: 206-515-5628 or jbrunner@seattletimes.com