Jackie Speier's announcement on Tuesday that she will not seek another term in the U.S. Congress has created a rare political opportunity for elected officials throughout the 14th Congressional District, who seldom get a chance to run for an open seat.

But any speculation over who will seek to succeed Speier, D-San Francisco/San Mateo, a political icon who won her first election 41 years ago, hinges on a major wild card: The district that Speier has been representing is in the midst of being reshaped and its boundaries won't be known until late December. The redistricting process, which could result in some would-be candidates falling outside the lines of the heavily Democratic district, is adding a layer of complexity to plans to find Speier's successor. While the U.S. Constitution allows candidates to run for a seat outside their district, provided they live in the state, the shift could deter candidates concerned about being perceived as outsiders by the district's constituents.

The draft map that the California Citizens Redistricting Commission released last week, shows shifts in the northern and southern portions of Speier's district, which would no longer include the spacious coastal area south of Half Moon Bay and east of Woodside. Those cities would now fall into the new District 18, which is represented by Rep. Anna Eshoo, D-Palo Alto. A portion of Redwood City would also shift from District 14 to District 18, an adjustment that could deter political aspirants from the city to vie for Speier's seat. The same applies to East Palo Alto, which is currently in Speier's district but which would be in Eshoo's under the draft map, which is subject to further adjustments before its expected adoption in late December.

The portion of San Francisco that is part of District 14 would also shift, moving from the western neighborhoods of Sunset and Parkside to the Ingleside and Excelsior neighborhoods in the south and southeastern sections of the city.

But even despite these uncertainties, the race to succeed Speier is expected to have no shortage of candidates, numerous elected Democrats who were interviewed by this news organization predicted Tuesday.

"I think there will be a big scramble," said Jerry Hill, who represented the Midpeninsula in the state Assembly and the state Senate between 2008 and 2020 and who served as a San Mateo council member and a county supervisor before then. "A lot of people will be running, certainly, because of the fact that this is a once-in-a-generation event."

Assembly member Kevin Mullin, D-South San Francisco, who has been representing the northern portion of San Mateo County in Sacramento since 2012, is expected to be the prominent candidate should he choose to enter the race, according to Hill and other current and former elected officials. Mullin currently serves as speaker pro tempore in the Assembly, the second highest position in the Legislature's lower chamber. He won 75% of the votes in his most recent reelection effort, in 2020, and his political resume includes a stint as district director for Speier during her days as a state senator.

In a Tuesday statement, Mullin called Speier an "icon and a legendary figure in San Mateo County and California legislative and political history." And as her district director, he said he "was awed by her ability to stand up to powerful interests regardless of potential political consequences."

"It was the embodiment of integrity, with a fidelity to the public interest above all other considerations," Mullin said.

On Wednesday, Mullin confirmed what many have suspected with a tweet: "With the announcement by my mentor, Congresswoman Jackie Speier that she will be retiring after a legendary career in both the CA State Legislature and U.S. Congress, I am seriously considering a campaign to succeed her in the United States House of Representatives."

State Sen. Josh Becker, a Menlo Park resident with a proven record of winning in San Mateo County, is also viewed as a possible candidate for Speier's seat, according to Hill and other Democrats who spoke with this news organization. His senatorial district covers much of Speier's turf, though it's not clear whether his hometown will fall under her congressional district under the new maps. Currently, Speier represents the Belle Haven neighborhood in Menlo Park, while Eshoo represents the remainder of the city. The draft map currently under consideration would shift Belle Haven to Eshoo's district.

Becker, who was elected to the Senate in 2020 and who has strongly advocated for climate-change legislation, would not confirm Tuesday whether he will seek Speier's congressional seat, which candidates are allowed to do even if they don't reside in the district. In a statement Tuesday, he called Speier a "true superhero" who has "done so much for the people of the Peninsula, our state and our country." He did not, however, respond to an inquiry about the political implications of her decision not to seek reelection.

"That should be our focus today: honoring Jackie for all she has accomplished. Her legacy is tremendous at every level of government," Becker said in a statement.

Palo Alto Vice Mayor Pat Burt was among those who cited Mullin and Becker as the two most prominent potential contenders in San Mateo County, though he was quick to note that neither has declared his intention to run.

"There are a few real top-tier folks currently in San Mateo County and none are yet indicating whether they are open to pursuing this spot," Burt said. "I think they're both exceptionally capable."

Assembly member Marc Berman, whose district includes Menlo Park, Palo Alto and Mountain View, said he is not considering a run for Speier's seat because he does not live in her congressional district (notwithstanding the fact that this is allowed by law). He predicted, however, that there will be no shortage of candidates.

"It's not every day, it's not every year, it's not every decade that a seat opens up on the Peninsula," Berman said.

Berman declined to speculate about who will vie for seats but noted that any successful candidate has to have a demonstrated ability to build relationships across the dozens of small communities that make up San Mateo County. Unlike Santa Clara County, which is dominated by San Jose, and San Francisco, which is both a city and a county, San Mateo County doesn't have a clearly established power base.

"I think San Mateo County is a unique place," Berman said. "It's a lot of small cities — there is not one big city that sucks it all up. So it has to be someone who has developed relationships in all those communities, someone who has shown an ability to get along well with colleagues."

While the decentralized nature of San Mateo County makes it hard for local mayors and council members to win broad political support, the county's composition also gives a natural advantage to members of the San Mateo County Board of Supervisors, who benefit from a broader geographical reach and greater name recognition (the advantage is somewhat mitigated by the fact that the county has district elections, which limit each supervisor's political base to their specific district). Speier herself served as a county supervisor between 1980 and 1986, before she began her 20-year stint in Sacramento.

Several political veterans who spoke to this news organization thus see David Canepa, president of the Board of Supervisors, as a potential candidate for Speier's seat. William Silverfarb, Canepa's policy aide, did not respond to this news organization's inquiry about Canepa's possible candidacy, though he told the San Francisco Chronicle on Tuesday that Canepa is "definitely considering running for this seat."

Another name that has come up in interviews is that of Redwood City Vice Mayor Giselle Hale, who did not respond to an inquiry about her potential candidacy.

The race is expected to start taking shape relatively quickly, given that California's primary election is set for June 7. On Tuesday, politicians throughout the region who had served with Speier in Sacramento or Washington, D.C., lauded her legacy as a legislator. Hill, whose term in Sacramento and political constituency both overlapped with Speier's, said he was particularly struck by her commitment to the people of her district. He said he constantly runs into people around town who have stories about Speier helping them out.

"Her constituents always feel a strong comfort level and confidence in her leadership," Hill said. "You can't say that about a lot of people."

Burt called Speier "a courageous person in both Congress and in her personal life" and lauded her "great compassion in general and a great commitment to her district." Santa Clara County Supervisor Joe Simitian, who as a former state senator also represented a large swath of San Mateo County, called Speier a "first-rate legislator," while Belmont Mayor Charles Stone said she was a "legend in her own time."

"She is a woman who has done more for the Peninsula than most people could do in 10 generations. Her story is one of tragedy and triumph, and I'm incredibly grateful to her for her service in San Mateo County," Stone said.