How much will Donald Trump matter as California’s Senate candidates debate?

The four top candidates in California’s increasingly tight, brutally-fought Senate race will debate for the final time Tuesday night–and Donald Trump is likely to share the spotlight.

Former baseball star Steve Garvey is the only Republican scheduled to appear with Democratic Reps. Adam Schiff of Burbank, Katie Porter of Irvine and Barbara Lee of Oakland in the one-hour debate, which will be televised live from the Universal Studios Hollywood Lot.

The top two finishers compete in November. A new Emerson College Poll released Monday showed Schiff widening his lead since January with 28% of likely voters, while Garvey was second with 22%, up six from last month. Porter trailed with 16% , up 3 percentage points from a month ago, while Lee had 9% this time, up one.

The debate will be available through Peacock, Roku, Samsung TV Plus, Amazon FireTV and NBCLA on Facebook and YouTube and Telemundo 52 on Facebook and YouTube

Trump elbowed himself into the race last week with a message on his Truth Social account. He branded Schiff “Slimeball Adam ‘Shifty’ Schiff,” and “one of the true lowlifes in the history of politics in America.”

Trump has not endorsed Garvey or anyone else in the Senate race. Garvey has been careful not to endorse Trump.

Voters will be choosing candidates in two races, one to fill the remaining months of the late Sen. Dianne Feinstein’s term, which runs through January, and the other for a full six-year term.

Newsom appointed Sen. Laphonza Butler, D-Calif., to the seat in October but she is not running in either election.

The Trump factor

Tuesday’s debate will be the third between the top candidates this year. At both debates so far, Garvey has been pressed on his views of Trump.

Garvey says he voted for Trump twice, but will not say if he would vote for him this year. He said at last week’s debate he would “make that decision when the time comes.”

Democrats have continued to needle Garvey. At the first debate, Porter grew frustrated. “Once a Dodger, always a dodger,” she said.

Trump and Schiff have been bitter rivals for years. Schiff led the House effort to convict Trump in 2020 after he was impeached for courting foreign involvement in that year’s presidential election. Trump was acquitted in the Senate.

“Trump inserting himself into the campaign boosts Schiff because this plays into Schiff’s argument in a Democratic-dominant state where a majority of voters don’t like Trump. It also might help Porter a bit too,” said Christian Grose, academic director of the University of Southern California’s Schwarzenegger Institute.

Schiff is using what he sees as the threat of Trump to help his campaign. “The single greatest threat to our democracy is the twice-impeached, criminally indicted former President who incited an insurrection on our Capitol,” the congressman said Friday in a fundraising appeal.

Because Trump tends to mobilize voters from both parties, Porter can also benefit, Grose said.

Lindsay Reilly, Porter’s press secretary, said “Katie is clear-eyed about the threats posed by Donald Trump and the need to defeat him this November, but she also hears from Californians that they want a forward-thinking leader — not someone who’s exclusively focused on Trump.”

Porter stresses her background as a fierce consumer advocate. Reilly said Porter “understands there was corruption in government long before Trump and that there will be corruption in government long after. That’s why she’s focused on both standing up to Trump and rooting out corruption so that we can make progress on issues like housing, climate, and health care.”

Lee, who has been in fourth place in recent polls, has strong backing among progressives and is counting on mobilizing a grassroots effort to crack the top two. She has also criticized Trump, tweeting this week “Donald Trump is a threat to our democracy.”

“Donald Trump incited an insurrection against the United States government. But no one, including the president, is above the law. The protection of our democracy is my top priority,” she said. Lee is the lead plaintiff in a lawsuit that would hold Trump accountable for the Jan. 6 Capitol insurrection. Trump has claimed he has immunity from such action, but a federal appeals court ruled otherwise.

Garvey too could benefit from more Trump visibility. If Trump becomes a big Garvey backer, “that could help Garvey make it through on the winds of Republican voters,” Grose said.

If Garvey qualifies for the general election, though, Trump is likely to be a liability. In 2016 and 2020, Trump lost California by huge margins. The latest Berkeley IGS poll showed that in a November field with third party candidates, President Joe Biden leads Trump 47% to 31%.

The survey polled 8,199 registered votes Jan. 4 to 8. Margin of error is plus or minus 1.5 percentage points.