As her tenure as Assembly speaker winds to a close, Toni Atkins is preparing for her next major political battle: intra-party combat.
Atkins is taking on state Sen. Marty Block for his San Diego seat, a highly unusual challenge in a political culture that privileges — and fiercely protects — incumbents.
"Absolutely it makes me uncomfortable," Atkins told The Times. "Will I be prepared to do it? Absolutely."
The brewing showdown could cause fractures not just in local San Diego Democratic politics, but in the state Capitol, escalating a long-simmering rivalry between the Senate and Assembly that persists even as Democrats solidly control both chambers.
"The soon to be ex-speaker knows very well that when one house challenges another, it's a slap in the face of the leader of the challenged house," Block said. Or put another way, the senator said, "This is a direct attack on Kevin De León."
De León, the Democratic leader of the Senate, declined to say if he saw Atkins' bid as an affront. In a statement, he praised Block's "principled leadership" in pushing for more higher education funding in the most recent budget and called his colleague "an extraordinary senator."
"He deserves to be reelected and Senate Democrats are resolutely united behind him," De León said.
For her part, Atkins said her relationship with De León is good and that she hopes "there will continue to be mutual respect."
In taking on a sitting senator, Atkins is attempting to pull off an exceedingly uncommon feat. Alex Vassar, operator of the California elections database OneVoter.org, said he could find only three instances where a sitting senator was defeated by an Assembly member. But an Assembly speaker taking on a senator of her own party is "shocking," he said.
Atkins opted against running against Block when the Senate seat was open in 2012 and they both served as Assembly members. He was first elected in 2008; Atkins won her seat two years later.
She said her decision was the result of a meeting with Block in which he indicated that he'd only serve one term. Block denies any commitment was made in what he described as a speculative conversation.
"We discussed it, but there was no backroom deal at all," he said. "I wouldn't be a part of any backroom deal."
Two political figures involved in the conversations with Block at the time — then-Speaker John A. Pérez (D-Los Angeles) and Jess Durfee, who was then the chair of the San Diego County Democrats — say Block was more direct in saying he'd step aside in 2016.
Atkins said she operated under that assumption for the next several years, as she became Assembly speaker in 2014. As leader, she won praise for helping craft a $7.5-billion water bond that won nearly unanimous support in the Legislature before being approved by voters last year.
But this year she was unable to advance her major priority: a bill to expand affordable housing. She also has faced criticism for being unable to hold together her large caucus, comprised of many ambitious lawmakers elected under longer term limits.
Earlier this month, Democrats tapped Assemblyman Anthony Rendon (D-Los Angeles) to succeed her next year. The leadership change may mitigate some hostilities between the legislative houses, said Dan Schnur, director of the Jesse M. Unruh Institute of Politics at USC.
"If she were going to be coming back as speaker next year, she would have to work directly with the Senate leadership. And that would create all sorts of tension," Schnur said. "The fact that she's a lame duck moves it from an institutional problem to a personal dispute."
Atkins complained that Block "has put me in a position that is really unfair."
"What is most offensive is, of course, the whisper campaign that makes me out to be some big bully that wants to push him out of his rightful seat," she said.
Atkins' leadership role has put her in a strong fund-raising position. She has more than $600,000 in cash on hand in an account for a 2020 Senate run that she can legally put toward this 2016 run. She also has more than $900,000 leftover from her 2014 run, some of which she could use.
Block, who has just under $80,000 in the bank, said he was confident De León and Senate Democrats will help overcome the money gap. In fact, Block said the Senate leader has told him "he'll do what's necessary to win this race."
Spending money on a fight within the party for a safely held seat —Democrats hold a nine-point registration advantage in the 39th District, which includes most of the city of San Diego, as well as Coronado and Del Mar — would have little appeal in any state, but even less so in California given the election rules enabling the top two vote-getters to advance to the general election regardless of party. That means the Block-Atkins contest could last until November, carrying a high price tag.
Earlier this week, De León waded into another race dividing the Democratic Party, endorsing U.S. congressional candidate Ro Khanna in his second bid to challenge Rep. Mike Honda (D-San Jose).
The potentially bruising fight could make foes out of politicians who have, until now, been cordial, if not especially close. Atkins endorsed Block in his 2012 run and donated to his campaign. And the two lawmakers have nearly identical voting records. Both get high marks from core Democratic constituencies such as labor groups, environmentalists and gay rights advocates.
"If she has some major difference with me on policy issues, she has not expressed it, nor has she voted it," Block said. "I think the ball is in her court to show why she would challenge a sitting incumbent."
Atkins said her leadership role will be integral to her pitch to voters.
"I'm the speaker. I've actually made things happen, being the first speaker from San Diego, being able to bring things home for my community…. I think I'm just a better return on investment long-term," she said.
Atkins' decision has divided San Diego politicos. Assemblywoman Lorena Gonzalez (D-San Diego), an early endorser of Block's campaign, said Atkins' challenge could be "devastating" for the liberal political scene, which has battled against the area's historically Republican tilt.
"This intra-party fighting – we're just not mature enough yet. We're not steady enough," Gonzalez said.
But Atkins supporters pushed back against the notion the run was a major breach in protocol.
"Toni has every right to run for this seat, and to put her reputation and best foot forward and let the voters decide," said Christine Kehoe, a political mentor of Atkins' who served on the San Diego City Council and then represented the city in the Assembly and Senate.
John Burton, chair of the California Democratic Party, declined to comment, as did an aide to Gov. Jerry Brown.
Pérez said he hopes a rough Democrat-on-Democrat fight could be avoided.
"My hope is that my friend Toni Atkins and my friend Marty Block sit down, and at the end of the day, only one of them is running for Senate," Pérez said.
Follow @melmason for more on California government and politics.
For more on California politics, go to latimes.com/politics.