Barbara Boxer speaks to volunteers for Democratic presidential candidate Hillary Clinton on Oct. 29 in Cincinnati. (John Minchillo/AP)

Barbara Boxer’s original plan was to drift into retirement, occasionally using a “sleepy little PAC” to help some former colleagues and “reelect Hillary Clinton” in 2020.

Instead, the fiery California liberal has reassembled her old Senate campaign advisers and created a “hybrid” PAC to fund attack ads against Republicans. With a new motto — “resist and replace” — her political focus is trained on boosting House Minority Leader Nancy Pelosi, a longtime friend, by targeting seven House districts in California.

Since leaving the Senate in January, Boxer has been making private speeches and media appearances, including one next month debating former House speaker Newt Gingrich on health-care issues. And, for someone who never was accused of holding her tongue, Boxer feels unburdened to say whatever she thinks about the “Trump enablers” with whom she used to work.

“For the first time in 40 years, I’m unleashed and I’m uncensored,” she said in a recent telephone interview from the Bay Area.

This is one of the more unusual post-Senate careers in recent memory. Rather than heading to a K Street law or lobbying firm, and instead of taking over a special-interest association, Boxer, 76, has decided to focus on elective politics.

After four decades in politics, she remains connected to the fight against President Trump, without the day-to-day grind of being a legislator.

Some weeks are going to be more jarring than others for a full-fledged member of the “resistance.” This past week brought one of the more unexpected twists, as Boxer’s old friends became first-name buddies — “Chuck and Nancy” — with Trump.

The president sided with Senate Minority Leader Charles E. Schumer (D-N.Y.) and Pelosi (D-Calif.) on how to handle legislation to avoid a government shutdown and a default on the federal debt. By passing a short-term increase in the Treasury’s borrowing authority, the Democratic leaders forced Republicans into another lift of the debt ceiling early next year — a politically perilous task from which Democrats hope to leverage concessions on immigration and health-care issues.

Trump even made follow-up calls Thursday morning to talk about how good the media coverage was of their bipartisan deal, issuing a tweet at Pelosi’s request saying that hundreds of thousands of undocumented immigrants brought to the United States as children should not fear deportation over the next six months.

It was a classic insider move by two classic insiders, winning plaudits from their colleagues but creating apprehension among some liberal activists who want constant confrontation with a president whom they deem unfit for office.

Boxer has no plans to serve as an armchair quarterback about how her close friends make their decisions. She just wants to help Pelosi and Schumer knock off as many Republicans as possible in next year’s midterm elections.

Still, so much keeps happening that Boxer finds it jarring to watch from 3,000 miles away. “I feel like it’s been three years since I’ve been in the Senate,” she said, not even eight months out of office.

PAC for a Change was originally a federal leadership committee similar to what most members of Congress have, limited to $5,000 donations and corresponding contributions to candidates for office. In retirement, Boxer expected to keep doling out those checks to her former Senate colleagues and possibly serve some informal advisory role in the Clinton administration.

Within days of Trump’s upset, Boxer called her longtime campaign manager, Rose Kapolczynski, and her fundraising team. They converted that PAC into two parts: a traditional portion to directly support candidates and a sidecar that is essentially a super PAC collecting unlimited checks.

Speakers at her first few fundraisers included Pelosi and comedian Chelsea Handler, as well as Rep. Adam B. Schiff (Calif.), the outspoken Trump critic who is leading the Democratic side of the House Intelligence Committee’s investigation into whether the president’s campaign had ties to Russia.

As of June 30, Boxer’s PAC had collected more than $1.3 million, more than $1 million of which came from mega-donors such as the feminist Peg Yorkin, who gave $150,000, and Eli Broad, who donated $50,000, and Andy Khawaja, the billionaire founder of e-commerce giant Allied Wallet, who contributed $100,000.

This violates Boxer’s belief that unlimited donations should be outlawed, but she’s willing to endure the charge of hypocrisy as long as conservative groups collect even larger checks from mega-donors.

“I’m going to play by the same rules as the Koch brothers,” Boxer said in a reference to Charles and David Koch. The billionaire brothers donate to politicians and political causes.

The super PAC’s first volley into campaigns is a digital ad going after Rep. Darrell Issa (R-Calif.) for his vote to repeal the Affordable Care Act, which features an irreverent video showing Issa as a bobblehead as a hip-hop track plays.

Boxer sounds almost like Trump in describing Issa — “very mean-spirited person” — and notes that he tried to challenge her in 1998 but lost the GOP primary.

Issa sits in one of seven California districts that supported Clinton last year but backed a Republican for Congress, making those seats prime targets for Democrats in next year’s midterm elections. They need a net gain of 24 seats to win back the majority. Boxer noted that all seven of those California Republicans voted to repeal the ACA, something her PAC will focus on in future ads against those GOP lawmakers.

Ultimately, Democrats need to do more than criticize Republicans. Boxer believes that the 2016 disappointment came about because there was never a full reunification of the wings that backed Clinton and Sen. Bernie Sanders (I-Vt.) during the primary.

“We have to marry up the two sides,” she said. “If we stand in our corners, that’s a losing strategy.”

She wants a truly wide-open 2020 presidential primary to help heal those wounds, which could be considered slight criticism of how the Democratic National Committee handled last year’s race amid charges of Clinton favoritism.

“It’s time to see who can organically build the coalition,” she said.

And depending on how successful she is, Boxer will be ready in three years to use her super PAC to boost whoever emerges in “untethered” fashion: “This is the moment when you want to be free to say what you want.”

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