It was her first morning event, and Sen. Dianne Feinstein already was running late. She was going to a South Bay wildlife refuge to give a speech that was billed as nonpolitical, but nothing an officeholder does in an election year is nonpolitical.

So it was no surprise that Feinstein, who is being challenged from the left in November by a fellow Democrat, state Sen. Kevin de León, went straight to the pitch that has kept her in the Senate since 1992.

The $177 million federal grant she pushed through for a 4-mile-long levee and wetlands restoration project at the Don Edwards San Francisco Bay Wildlife Refuge in Alviso came after more than 20 years of work and bipartisan negotiations, she said.

“We can get all people together, Republicans and Democrats, to work across the aisle for something we believe in,” Feinstein told the crowd.

But it’s a different political world than it was in the 1990s. With Donald Trump in the White House, Feinstein’s kind of deal making isn’t just out of favor — many Democrats view it as collaborating with the enemy.

In today’s California, a kind word for Trump or almost any other Republican can be taken as evidence of a Democratic candidate’s unfitness for office. Feinstein learned that last year when a crowd in San Francisco booed her for saying that if Trump could “learn and change,” there was the possibility that he “can be a good president.”

Her suggestion that people “have to have some patience” with the Trump administration contributed to the uproar. Those statements, de León has said, persuaded him to jump into the Senate race.

“In your state Senate, Democrats act like Democrats,” de León told delegates at the state Democratic Party convention a few months later. “We demand passion, not patience.”

The contrast between an understated old-school politician like Feinstein and the new breed of Democrat was on display during the Senate Judiciary Committee’s confirmation hearing for Trump’s Supreme Court nominee, federal appeals Judge Brett Kavanaugh.

Feinstein’s California counterpart, Sen. Kamala Harris, got a tip that Kavanaugh had been talking with lawyers at a Trump-linked law firm about Special Counsel Robert Mueller’s investigation. Harris didn’t have enough to go public with the details, but that didn’t keep her from using her question time to grill Kavanaugh — who denied he’d had any such talks.

But when Feinstein received her own tip — a letter that alleged Kavanaugh had attempted to sexually assault a girl while they were both in high school, according to the New York Times — she said nothing at the hearing and refused to publicly discuss its contents when word of it leaked out last week. A spokesman said she wanted to go public, but that the alleged victim insisted on keeping the information private. Feinstein gave the letter to the FBI on Wednesday.

De León echoed the reaction of many progressives to Feinstein’s overall questioning, saying she had “pantomimed her way through (the) hearing without a single question about the content of Kavanaugh’s character.”

For Feinstein, her handling of the letter was a matter of passing up a chance to score political points, even against a nominee she opposes. Confrontation isn’t her style.

She’s given up hope that Trump will be a good president, she said, but he and the Republicans are still a fact of life.

“I don’t agree with Donald Trump, I didn’t vote for Donald Trump, I don’t support Donald Trump,” Feinstein said. “He is not my person of choice for the presidency. ... But he still signs or vetoes bills.”

With Republicans in control of the Senate, the only way to get anything done is to work with the other party, Feinstein added.

“I have a bill that says (undocumented immigrant) children cannot be separated from their parents and every Democrat is on it, but that’s not enough, obviously,” she said. “So I’ve been trying to negotiate with (GOP Sen. Ted) Cruz to see if we can come up with a bill that we can both agree to.”

From the day the former San Francisco mayor was first elected to the Senate, that call for bipartisan engagement has been Feinstein’s signature. When she pushed the California Desert Protection Act through the Senate in 1994, she did it by dealing with Republican concerns about private property and existing commercial uses on land that would be designated as wilderness.

Most Republicans had opposed the bill, which had been introduced years before by Sen. Alan Cranston, D-Calif. “But Sen. Feinstein showed a willingness to solve problems rather than trumpet the issue,” said then-Sen. Robert Bennett, R-Utah.

In 2008, Feinstein and then-Alabama GOP Sen. Jeff Sessions collaborated on a law that cracked down on online pharmacies that sold controlled substances without prescriptions. In 2006, she worked with then-Sen. Jim Talent, R-Mo., on a bill restricting the sale of ingredients needed to cook methamphetamine. In 2003, she and then-Sen. Kay Bailey Hutchison, R-Texas, helped persuade President George W. Bush to create the nationwide Amber Alert network for abducted children.

“I have to work with the other party when the other party is in control,” Feinstein said.

But even she admits that the Senate, and national politics in general, have become far more partisan.

When Feinstein took up her landmark bill to ban the sale of assault weapons in 1994, the Democrats were in charge of the Senate. But Sen. Bob Dole of Kansas, the GOP leader, called for a decision on the bill.

“Dole stood up and said, ‘This is a big bill. This is an important bill. It deserves to be debated on the floor of the Senate,’” Feinstein recalled. The ban passed both houses of Congress but expired in 2004.

In the current environment in the Senate, a bill that controversial would have no hope. On virtually every major legislation, “you have to get 60 votes to bring it to the floor or 60 votes to close debate and 60 votes to pass it,” Feinstein said. “So it essentially changes a majority vote to a supermajority. ... It makes it very hard (for the minority) to pass anything.”

Feinstein admits that the hard partisan turn is a new experience for her.

“One thing I’ve never been is a name-caller,” she said. “And if what people want is their senator shouting epithets, I’m not the one. And it’s not going to accomplish anything.”

Before the Kavanaugh hearing, Feinstein fought to have Republicans release millions of pages of documents related to the years the nominee spent as a White House aide to Bush. When the time came for public testimony, however, Feinstein’s questions were pointed but polite. She focused on issues such as his stands on abortion rights and gun control, mostly avoiding the harsh attacks that came from other Democrats.

When Feinstein apologized to Kavanaugh for protesters’ disruptions of the hearing, de León and other progressives argued that was proof she was the wrong person to represent California in the Trump era.

Feinstein shouldn’t be respecting “country club rules,” de León said. “We should be praising the protesters and standing outside with them, not apologizing for their actions.”

Feinstein’s moderate instincts were reinforced by her early days in San Francisco politics. She “was the least political elected official I have worked with,” said Jim Lazarus, a senior vice president of the city’s Chamber of Commerce who was Feinstein’s deputy mayor. “Some of this may have come from the nonpartisan nature of local government until the early 1990s. Political parties couldn’t endorse during her years running for supervisor and mayor.”

That also meant she didn’t owe anything to Democratic Party leaders and activists, as they discovered when Feinstein ran for governor in 1990.

An early underdog in the primary campaign against state Attorney General John Van de Kamp, Feinstein drew boos when she went to the state Democratic Party convention and talked about her support for the death penalty.

But Feinstein’s campaign had a film crew at the convention, shooting her speech and the angry reaction of the crowd. She quickly put up a TV spot touting herself as the only Democratic candidate in favor of the death penalty. She beat Van de Kamp in the primary, only to lose the general election to Republican Sen. Pete Wilson.

She has moved leftward during her years in office. In particular, the tough-on-crime persona has mellowed. She no longer favors the death penalty and has dropped her opposition to legalization of recreational marijuana use.

“I don’t want to not grow, I don’t want to not learn,” she told reporters in May. “The world changes and views change and we change.”

Feinstein hasn’t flipped on all the hot-button issues. She remains an opponent of single-payer health care, arguing that it’s hard to see where the money would come from.

Instead, she said, “I’ve supported a public option of insurance to compete with the private sector. I support lowering the age of access to Medicare to 55.”

Feinstein also pushes back against progressive Democrats’ call for Trump’s impeachment, which de León supports.

“What has to happen is an election,” Feinstein said. “And that’s how people are replaced, in an election.”

She added, “If you want to be a senator just to vote on impeachment, that’s not a good reason to be a United States senator.”

But many Democratic activists are moving away from her. In a harsh rebuke to Feinstein, the state Democratic Party’s 330-member executive board overwhelmingly endorsed de León in July.

Feinstein’s allies blamed that on the takeover of the party’s internal apparatus by pro-Bernie Sanders progressives and said it wasn’t representative of rank-and-file Democrats’ sentiments. But those progressives, impatient with Feinstein’s collegial and compromise-friendly Senate style, may also be her party’s future.

There probably aren’t enough of them yet to blunt her re-election chances. She easily won the June primary, even beating de León in the legislative district he represents in Los Angeles.

“Having de León run to the left and seeking progressive support is the perfect strategy for Feinstein,” said Darry Sragow, a former Democratic strategist who now publishes the California Target Book, which focuses on state political races. “There are far more people to Feinstein’s right than there are to her left.”

A bigger challenge to Feinstein could be her age. At 85, she is already the oldest member of the Senate. While de León and other opponents are careful not to raise the age issue directly, there are regular wink-and-a-nod calls for “new blood” and “a new generation of leadership.”

Feinstein said she spent a lot of time thinking before she decided to run for re-election, looking at “whether I wanted to do it, whether I felt I could continue to do it for a length of time. All the signs were ‘yes’ on both.”

She said she doesn’t let concerns about her age bother her.

“My health is good,” she said. “I don’t think age is chronological. I think age is mental and it’s physical.”

In her view, the years she has spent in office, the work she’s done and the contacts she’s made are reason enough to vote for her.

Before making her speech at the South Bay wildlife refuge, Feinstein played the politician and spent her first few minutes greeting old friends, people she had worked with for more than two decades to get the project moving.

“You’ve been great,” she said to one. “It’s been so many years,” Feinstein told another.

Her ability to cobble together bipartisan alliances and get things done is what people should focus on in November, she said after the talk.

“I’m not one who beats people up,” Feinstein said. “I just want people to understand how much I care about this state and doing the right thing, the positive thing on behalf of the people who live here.”

John Wildermuth is a San Francisco Chronicle staff writer. Email: jwildermuth@sfchronicle.com Twitter: @jfwildermuth