For left-leaning Californians, there’s a silver lining to the Trump administration’s proposal to reopen the long-protected California coast to offshore oil drilling: They think it could help them win back Congress from the Republicans.

They hope the ensuing political blowback will make it easier to rally Democratic voters against seven GOP congressmen who represent districts that supported Hillary Clinton last year, especially in two districts along the Southern California coast. Democrats need to win 24 GOP-held seats nationwide to regain control of the House.

“It just made part of my job a whole lot easier and part of it a lot harder,” Michael Brune, executive director of the Sierra Club, the nation’s largest environmental group, said Friday.

Brune is among those who believe the Trump administration is at war with California values, and in that war three more battlefronts intensified this week.

On Thursday, U.S. Attorney General Jeff Sessions urged the nation’s federal prosecutors to disregard state marijuana laws and file criminal charges in states, like California, where cannabis is legal. Also on Thursday, the administration said it would vastly increase the number of offshore drilling leases to boost the nation’s energy supply.

Earlier in the week, Thomas Homan, the acting director of U.S. Immigration and Customs Enforcement, singled out California when he said government officials who support sanctuary city policies should be jailed.

Those positions may play well elsewhere in the country, but not in California, said Mark Baldassare, president of the nonpartisan Public Policy Institute of California, which has polled extensively on political issues for decades.

“When you’re looking at issues like cannabis or oil drilling or immigration, Californians’ opinion on these issues have been settled for many, many years,” Baldassare said. “We’ve seen majority support for marijuana legalization, overwhelming opposition to oil drilling and overwhelming support for a pathway to citizenship” for immigrants in the U.S. illegally.

However, Baldassare said it’s too early to predict how the administration’s recent initiatives will shape the state’s midterm elections, in which Democrats are targeting seven GOP-held House seats in districts that Clinton won. But his recent surveys show that more people are paying attention to and getting involved in politics.

But the administration’s actions “will likely affect who comes out to vote and how many people come out to vote. People want to express how they feel,” he said.

Only 1 in 3 likely California voters approves of Trump’s job performance, Baldassare said. That could be one reason that GOP leaders are urging incumbent Republicans to “vote their district,” said Jack Pandol, a spokesman for the National Republican Congressional Committee.

“These issues allow members to demonstrate their independence,” said Pandol, noting that Rep. Dana Rohrabacher, R-Costa Mesa (Orange County), a longtime leading voice for marijuana legalization, criticized Sessions this week.

California Republican Party Chairman Jim Brulte thinks the effect of this week’s developments “will be minimal.”

“Voters distinguish between candidates and the policies of other elected officials,” Brulte said Friday. “The Republicans that the Democrats are targeting are all very well known in their districts.”

Brulte said the idea that this week’s actions were the latest examples of a “war” between the Trump administration and California “is kind of crazy.”

Some Democrats have said that the GOP tax cut legislation that Trump signed was designed to punish high-tax states like California, New York and New Jersey, which overwhelmingly supported Clinton.

“Most of the elements in this tax reform have been part of the Republican congressional agenda since before Donald Trump was a Republican,” Brulte said.

Even though Proposition 64, which legalized recreational cannabis, passed with 57 percent of the vote in 2016, Democratic organizers say it is difficult to tell whether the threat to cannabis use in California will inspire a grassroots army to knock on doors in targeted congressional districts.

“But as the stigma continues to decrease (around cannabis) you may find more people pulling out their checkbooks, if not marching in the streets,” said Doug Linney, campaign manager for Flip the 14, a new organization seeking to replace California’s 14 Republican members of Congress.

Linney said the real effect of the administration’s moves could be to “awaken the sleeping giant” of activists concerned about drilling off the coast. That could mean more headaches for Republicans representing coastal districts, which include Rohrabacher and Rep. Darrell Issa, R-Vista (San Diego County). The nonpartisan analysts at Inside Elections with Nathan L. Gonzales rate Rohrabacher’s seat “tilt Republican” and Issa’s a “toss-up.”

Their environmental voting record ratings from the California League of Conservation Voters won’t endear them to coastal preservationists, either. Issa’s 2016 score was 3 percent. Rohrabacher’s was zero percent.

Far from the coasts, the administration’s moves this week on oil, cannabis and immigration have jolted progressive activists living in conservative inland districts, like Paul Smith, the founder of Sierra Nevada Revolution. The new grassroots organization hopes to replace longtime Rep. Tom McClintock, R-Elk Grove (Sacramento County).

“It fires us up,” Smith said. “Certainly there are days where it’s hard not to get discouraged. But people here are so pissed at Trump and so pissed at McClintock. We see replacing McClintock as a way of stopping Trump’s agenda until we can replace him.”

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