Schiff started running an ad that attacks Republican Steve Garvey.
In post on X, formerly known as Twitter, Porter said in part, "Adam Schiff knows he will lose to me in November. That's what this brazenly cynical ad is about furthering his own political career, boxing out qualified Democratic women candidates, and boosting a Republican candidate to do it."
Garvey, on the other hand, didn't seem to mind.
"I'm really not running against my opponents. I'm running for the people of California. What they do is their business, but if Mr. Schiff wants me, he can have me so to speak," said Garvey.
Then, Porter decided on the same strategy.
Her campaign started running an ad highlighting the credentials of another Republican in the race, Eric Early.
If the ad helps early, it would take away support from Garvey, giving Porter a chance at that No. 2 spot in the likely November runoff election. Polls have shown a close race for second between Garvey and Porter.
In a statement, Schiff's campaign said in part "Steve Garvey will be a rubber stamp for Donald Trump's extreme agenda if elected. California voters deserve to know the differences between the two top-polling candidates."
On Tuesday, Garvey received the endorsement of the El Monte Police Officers Association, saying Californians need to feel secure.
"He listened. He listened to us and we expressed the issues facing police unions across the nation, not just here in our community. I think at the end of our conversation, we both agreed America is ready for a change," said El Monte Police Officers Association President Wyatt Reneer.
Central to Garvey's campaign is his career as a baseball player for the Los Angeles Dodgers and the San Diego Padres. His son, who works for the campaign, brings a box of Rawlings baseballs to events for Garvey to sign.
"We feel good about next Tuesday, but as you can see, we're in a stretch run," said Garvey. "I've done my stretching. My hamstrings are fine. I can still run a little bit. We are going to be, I think, honored by the people next Tuesday to allow us to go to, what I call, the season - 8 months, 9 innings - to get to that one championship game on November 5th."