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LA QUINTA, Calif. — Disgraced former National Security Adviser Michael Flynn campaigned for a Republican congressional candidate in California Friday in his first public appearance since pleading guilty to lying to the FBI.

Friday's event to endorse Republican Omar Navarro in his challenge of 14-term Democratic Rep. Maxine Waters is the latest signal that Flynn is re-entering political life while still awaiting sentencing and cooperating with special counsel Robert Mueller's investigation into Russian election interference and possible coordination with President Donald Trump's associates.

Mueller is also investigating possible obstruction of justice by the president. In recent weeks, the special counsel's prosecutors have signaled they want to interview Trump about his firing of Flynn and his conversations with former FBI Director James Comey about the FBI's investigation into Flynn.

Flynn said that he wasn't at the event in La Quinta "to complain about who has done me wrong or how unfair I've been treated or how unfair the entire process has been."

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Flynn is a retired Army lieutenant general who frequently campaigned for Trump during the 2016 presidential campaign and led the Republican National Convention crowd in anti-Hillary Clinton "lock her up" chants. He explained his decision to join the Trump campaign Friday, saying that his passion and destiny "changed when I saw our country taking a fundamentally different direction" and that he decided "to do something about it in a different capacity."

"If I'm paying the price for that decision, so be it and God can and will judge me at some point," Flynn said.

He said that the greatness of Americans is "our innate ability to get knocked down, to get right back up, shake it off and get right back into the fight."

Rep. Maxine Waters, Congresswoman for California's 43rd congressional district Chelsea Guglielmino / Getty Images

Navarro, a conservative Republican activist who lost to Waters by more than 50 percentage points in 2016 in the strongly Democratic district, slammed her in his remarks to the crowd. He called for Trump to endorse him and repeated a line from Trump that Waters has a "low IQ."

"Once November comes, you're going to lose, you're going to lose big," Navarro said. "Like the president said, your low IQ isn't going to get you past 2017."

Waters slammed Navarro and Flynn in a series of tweets, including noting that Navarro was on probation after being convicted of attaching a tracking device to his wife's car.

"Desperate, unstable, and convicted criminal Omar Navarro stoops low in soliciting help from another indicted criminal in a campaign against #MaxineWaters - what a campaign!" Waters tweeted .

"Apparently, the two will spend a lot of time together discussing their crimes," Waters said in another tweet.