Dissenting voices of a proposal to build a new arena in the Sodo District designed to lure the NBA back were nowhere to be heard at Occidental Park on Thursday.

Instead, a two-hour rally organized by Chris Hansen, the lead financier behind the plan, served as an opportunity to remember the Sonics' history and fire up those hoping for the team's return.

"Thank you, Chris," yelled a crowd estimated by Hansen's group at 6,000 — and by others at 2,000 to 3,000 — as Hansen took the stage to open the rally at 4 p.m.

"This is why I'm doing this, right here," he said motioning to the crowd.

For the next two hours, a steady stream of former Sonics took the stage, as well as politicians who support the proposal.

The former Sonics included Gary Payton, Slick Watts, Shawn Kemp and Detlef Schrempf. The politicians included King County Executive Dow Constantine, Seattle City Council member Bruce Harrell and King County Council member Bob Ferguson.

Constantine told the crowd that the proposal is the best the area will ever get to bring back the NBA and possibly lure an NHL team.

Backstage, he elaborated on that statement.

"This group of investors is making a remarkable offer to us," he said to reporters, referring to the investment group that also includes Erik and Peter Nordstrom and Microsoft chief executive officer Steve Ballmer. "They are going to bring hundreds of millions of dollars, and the government investment is going to be so completely secured that we are definitely going to get paid back, and paid far more than that in all the other taxes and other economic activity."

Speakers echoed a common theme: The turnout sent a message to politicians and to the NBA.

"I think it's great for them to see," Hansen said. "We all know what a great fan base we have. But this is a great opportunity to show the league and the NHL that we have great fans here in Seattle."

Hansen said he was initially taken back by the crowd. "I was about to tear up, actually," he said. "It was inspiring."

Several current NBA players with local ties also attended, hoping to have a chance to again play in their hometown.

Spencer Hawes, a Seattle Prep graduate and former Washington Husky now with the Philadelphia 76ers, wore a jersey of Hersey Hawkins, a member of the 1996 Sonics team that reached the NBA Finals.

"Hopefully, sooner rather than later, we'll be back here playing," he said.

Constantine also said he thought the turnout helped make a statement about the wide range of support for the proposal.

"I think there has been a lot of talk from people who have concerns or naysayers," he said. "But when you hear from the broad public — people who have been sitting, waiting and stewing about not having the Sonics — to finally get a chance to come out and say what they really think. ... It is a big turnout, a big crowd. And I think they represent many thousands of more people who just want this to happen."

Amid the speeches and cheers, music blared from bands, including Seattle band The Presidents of the United States of America.

Signs in Occidental Park urged participants to tweet their support to the City and County Councils, which are considering Hansen's proposal to contribute almost $300 million to the arena and another $500 million to buy an NBA team. The arena proposal would also require up to $200 million in public bonds. Hansen is scheduled to testify before the City Council on Wednesday.

Gubernatorial candidate Rob McKenna tweeted,"There is no red or blue in Seattle today — just green & gold!"

Marygrace Aguiling of Renton was one of the few women in attendance. She wore a T-shirt with the Sonics' logo and block letters that said "ROBBED."

"We need the Sonics back," she said. "It's part of what makes Seattle Seattle. There's a void here."

Hansen closed the rally on a more somber note.

"We're not there yet," he told the crowd. "There's still some work to do."

Backstage, though, he told reporters the rally reflected growing momentum.

"I think it's going well," he said. "People are going to ask hard questions. That's their job. And it's up for public debate. That's the way it should be."

Times staff reporter Lynn Thompson contributed.

Bob Condotta: 206-515-5699 or bcondotta@seattletimes.com.