For more than two decades, Palo Alto has tried to join an exclusive club that had declined to have the city as a member.

Time and time again, the city has attempted to land a spot in the SFO Community Roundtable, a panel that includes San Francisco and most San Mateo County cities and works with the San Francisco International Airport on the issue of airplane noise. Inevitably, its entreaties to join went nowhere.

Palo Alto's fortunes appeared to be shifting in June, when most group members signaled support for adding the city and appointed an ad hoc committee to explore changes to its criteria for welcoming new members. But on Wednesday, its bid join came crashing down in a familiar manner as roundtable members voted to exclude Palo Alto from its roster.

Following the recommendations of its ad hoc committee, a somewhat divided roundtable reversed course from its June direction and opted to keep its membership limited to the two counties closest to the airport. Opponents of allowing Palo Alto to join argued that expanding membership would compromise the group's ability to represent its existing constituents. While roundtable members from the Peninsula cities of Atherton and Portola Valley supported adding Palo Alto and argued that doing so would strengthen the group, most of the members from cities closer to the airport opposed its entry into the panel.

In recapping the ad hoc committee's discussion, roundtable coordinator Michele Rodriguez cited concerns by committee members about the "dilution of resources and priorities, and that we have an obligation to existing members."

Ricardo Ortiz, who serves on the Burlingame City Council, was among the ad hoc committee members who opposed Palo Alto's request. In explaining his position, Ortiz said he was concerned that once the roundtable allows one city from outside the county border to join, others would follow suit with similar requests and "it would be difficult for (the roundtable) to stop adding communities."

"Our mandate is, 'Do we open the borders or do we not?'" Ortiz said.

While 11 of his colleagues agreed that cities outside San Francisco and San Mateo counties should be denied entry, five others either voted against the committee's recommendation or abstained from the vote. Supporters of Palo Alto's bid to join the roundtable cast doubt on assertions that expanding the membership would drain the group's resources. Some pointed to the meeting's glaring irony: just minutes before roundtable staff rejected Palo Alto's membership on the grounds that the city would dilute the group's goals and require additional resources, the group's members swiftly and unanimously approved welcoming Colma into the roundtable — an addition that the panel proactively pursued.

The irony was not lost on Tom Hamilton, a San Bruno City Council member who supported Palo Alto's bid. Hamilton questioned why roundtable members cited resource issues when it comes to Palo Alto, but not when it comes to Colma.

"Using the 'dilution of resources' argument in all of its various flavors — it's a really bad look to do that, especially on the same night as we approved a new member," Hamilton said.

The most fervent advocate for Palo Alto's entry was Atherton City Council member Bill Widmer. He said he was disappointed in the committee's recommendation and suggested that the resource problems that committee members had identified could easily be solved by either increasing membership fees for all members or charging new members an entry fee. Adding Palo Alto, he said, would make the group stronger.

"I'm surprised we went out to recruit people when some people wanted to be part of it," Widmer said. "And we have to go to Colma to make a presentation and say 'Please join.'"

The division over Palo Alto's memberships has also created a rare fissure between Reps. Anna Eshoo, whose congressional district includes Palo Alto, and Jackie Speier, whose congressional district includes San Mateo County and a portion of San Francisco. The two U.S. representatives each submitted a letter, with Eshoo urging the roundtable to include Palo Alto and Speier encouraging it not to expand membership.

Eshoo suggested that her constituents and those in San Mateo and San Francisco counties have overlapping problems when it comes to airplane noise and would benefit from working together.

"I think your influence as a body will grow as you represent more communities because you will have more opportunities to build consensus across county lines," Eshoo wrote to the roundtable.

Palo Alto Mayor Tom DuBois similarly argued in his letter that the city's inclusion would benefit the entire group because the city shares the same goals as other roundtable members.

"Because Palo Alto's needs are similar to the needs of many SFO Roundtable members, the Roundtable's ability to solve the noise problems of current members will be strengthened because Palo Alto will bring additional resources and knowledge (technical and legislative), and continue its demonstrated commitment to solving aircraft noise problems in a collaborative manner," DuBois said.

Some, however, worried that Palo Alto's voice would drown out those of other communities. Speier suggested in her letter that the roundtable's obligation should be primarily to its existing member communities and framed it as a matter of "social justice equities."

"There are economic disparities between residents of many of your current member cities and residents of many Silicon Valley cities," Speier wrote. "Palo Alto, for example, is a well-resourced city and has shown itself to be fully capable of independently obtaining information and professional services and advocating their issues to decision makers."

Hillsborough Mayor Al Royse, who served on the ad hoc committee and who opposed Palo Alto's entry into the roundtable, said his concern was that if the group allows one city outside the county line to enter, it would have to extend the courtesy to all other cities that claim to suffer negative impacts from airplane noise.

"I'm not comfortable that we can add a member outside the county's boundary lines and stop there and be fair to everybody else," Royse said.

Despite some debate, the Wednesday decision became in some sense a foregone conclusion after the committee voted 6-1 last month to recommend not expanding roundtable membership (Menlo Park City Council member Cecilia Taylor was the only person who dissented and supported Palo Alto's potential entry). Changing membership rules requires support from two-thirds of the voting members and most of the roundtable members who represent cities in northern San Mateo County have consistently opposed Palo Alto's entry. Representatives from Brisbane, Daly City, South San Francisco and Millbrae all voted against allowing the city to enter, as had representatives from Half Moon Bay and Redwood City.

The recommendation to accept the committee's direction initially fell just short of the two-thirds requirement, with 11 members supporting it, three members opposing and two abstaining. John Carvell, who serves on the Woodside Town Council and who was one of the abstaining members, then changed his vote to "yes," effectively ending the debate.

The decision represents a stinging setback to Palo Alto residents who have been working on the issue of airplane noise since 2014, when the Federal Aviation Administration began instituting its NextGen Initiative, which established three arrival routes over Palo Alto. Palo Alto resident Rebecca Ward was among those who addressed the group on Wednesday and suggested that without collaboration, jurisdictions will have to explore options to address airplane noise in ways that may be less collegial.

"It benefits everybody to actually have a collegial way to solve problems and it needs to be through the SFO Airport and its official roundtable body," Ward said shortly before the vote.