Most of the candidates running for California’s up-for-grabs U.S. Senate seat were swaying so far to the left during Monday’s televised debate that even the Republicans were talking about raising the minimum wage, the problem of income inequality and how bad George W. Bush’s foreign policy was.

“I think we have to crack down on Wall Street, just like Bernie Sanders is saying,” said Republican Ron Unz, who lamented the “oligarchy” of the “financial elite” while complimenting a position of a Democratic candidate for president.

That was just one of the unexpected left turns Monday when, in an unusual moment in California politics, two Democrats and three Republicans shared a debate stage. Co-sponsored by The Chronicle, KCRA-TV of Sacramento and the University of the Pacific, the debate on the Stockton campus was one of only two multiparty primary debates scheduled before California’s June 7 primary and the only one to be televised live across the state and streamed digitally. The top two vote-getters in the primary, regardless of party affiliation, will face off in November.

Despite the bipartisan lineup, there were few clashes among the candidates and no sound bite zingers that will go viral. Instead of battling over partisan issues, the candidates, with the frequent exception of conservative former California Republican Party Chairman Tom Del Beccaro, frequently agreed on topics that would appeal to most voters in left-leaning California, where all statewide officeholders are Democrats and the Legislature is under Democratic control.

This probably was one of few chances for some of the candidates — particularly the underfunded ones who can’t afford TV ads — to stand out and reach a large statewide audience. Compared with the Democrats, the Republicans at Monday’s debate are cash-poor, particularly Del Beccaro, who had $77,946 cash on hand at the end of March, and Duf Sundheim, with $57,222 cash on hand.

The third Republican in the race, Silicon Valley businessman and writer Unz, barely acknowledged his party status Monday. He bragged about how a 12,000-word essay he wrote urging an increase in the minimum wage led to many states — including California — boosting theirs.

“I think I played a major role in moving the issue to center stage,” said Unz, who noted that he also talked up his idea to national labor unions — an act of blasphemy to many Republicans.

The Republicans needed to do something at the debate to play catch-up.

Democratic state Attorney General Kamala Harris, with 27 percent support in a Field Poll released this month, is far ahead of the pack and has almost $5 million cash on hand. Rep. Loretta Sanchez, D-Santa Ana, has 14 percent support and $2.3 million cash on hand.

If the two Democrats advance to the general election, as is likely, it will be highly embarrassing for the GOP.

Yet despite its importance, the presidential primary has so overshadowed the Senate race that a Field Poll of likely primary voters this month found that 48 percent were undecided. Roughly 3 in every 4 respondents had no opinion of the three top Republicans, and none of the GOP candidates polled more than 5 percent support. And that’s not even all of them. There are 34 candidates on the ballot to replace Barbara Boxer — 12 Republicans, seven Democrats and 15 third-party candidates.

Here’s where the candidates stood on some of the night’s key issues:

Immigration: Harris and Sanchez, whose parents emigrated from Mexico, support a pathway to citizenship for people in the country illegally. Sundheim outlined a middle course, calling for a pathway to legal status. And instead of building a wall, he suggested tapping into Silicon Valley for more tech solutions, like drones, to curb illegal immigration.

Then, in one of the most pointed attacks of the debate, he criticized Sanchez for missing most of the meetings of a House Committee on Homeland Security she serves on.

“It would be great if she went to the meetings,” Sundheim said.

Unz managed to connect immigration to raising the minimum wage. He would discourage illegal immigration, as “the vast majority of illegal immigrants come here for jobs,” he said. If the wage floor is lifted, “the magnetic pull of those jobs will disappear” because citizens will compete for those positions.

Minimum wage: Sundheim said he often works with low-income people near his South Bay home, but he disagreed with raising the wage.

“I am deeply concerned that the minimum wage will lead us down the wrong road.” Instead, he called for boosting the federal earned income tax credit.

Echoing a theme he repeated all night, Del Beccaro said government mandating a raise for low-income earners isn’t the answer. Instead, eliminating government regulations would free business to hire more people, and the ensuing economic growth would lift all people more than a hiking the base wage.

The Democrats and Unz supported raising the minimum wage, although Unz said California shouldn’t have boosted its wage to $15 an hour — $13 or $14 would have been more digestible for the Central Valley, he said.

National security: Asked whether President Obama has done enough on national security issues in the Middle East, Harris twice tried to dodge the question — Obama is a friend of hers and someone she supported before he ran for president. Finally, she said that Obama has done some good work, but more work needs to be done.

Sanchez, who voted against authorizing the Iraq War, said that too often Washington leaders consider the military option too soon.

Unz said that while Obama’s national security record was bad, “the Bush administration’s was even worse,” saying it destabilized the entire Middle East, which gave rise to terrorism in the region.

Education: Harris and Sanchez supported making community college free. When pressed how they would pay for that, Harris said students — armed with more education — would be able to land better jobs and pay more taxes.

Unz called for cutting tuition at the UC system and paying for it by trimming administrative jobs. Sundheim took a more conservative tack here, saying, “If you want to see something get real expensive, make it free.”

Chronicle staff writer Steve Rubenstein contributed to this report.

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli