Out of place in today's Democratic Party and in his own diversifying district on a host of issues including abortion, the six-term congressman is fighting for survival in Tuesday's primary election.
His conservative stances have made him the target of progressive activists who are fighting to purge the party of what they see as views that are anathema to its energized base during an election cycle that features more women running for office than ever before.
These activists, including groups like Planned Parenthood, NARAL Pro-Choice America and EMILY's List, are backing Marie Newman in a contest that has put a Democratic incumbent in serious jeopardy of being ousted by his own party for the first time since President Donald Trump took office.
It's turned Tuesday's contest into a both a purity test on the race's central issue -- abortion -- and a gauge of whether "Blue Dogs" have a future in Democratic politics beyond upset victories in red districts.
Campaigning at a Metra train station in a suburb outside of Chicago Monday morning, Lipinski stopped to chat as he passed out literature and shook the hands of commuters.
"We have to be an inclusive, big-tent party," Lipinski said.
In Lipinski's view, Democrats lost their way in the Obama years. The party focused far too much on identity politics in the 2016 presidential election, he says, alienating dissenters on social issues and losing focus of the economy.
He pointed to Democrats' loss of hundreds of state legislative seats during Obama's presidency.
"We have a long way to go, and it's certainly not the time to be pushing people out of the party, telling people they're not welcome," Lipinski said. "That was one of the problems -- it's why Donald Trump got elected in the first place, because Hillary Clinton was not being seen by some people in the Midwest as fighting for working-class men and women."
But that's exactly what has been happening here in Illinois' 3rd Congressional District.
The Democratic Congressional Campaign Committee, which typically protects incumbents, has sat his race out.
Former aides to President Barack Obama, still incensed that Lipinski voted against the Affordable Care Act due to its mandate that organizations offer health insurance that covers contraceptives, convened a press conference last week to settle the score.
Vermont Sen. Bernie Sanders rallied his political organization to Newman's cause, and two Illinois Democrats, Reps. Jan Schakowsky and Luis Gutierrez, took the rare step of endorsing a home-state incumbent's primary opponent.
Democrats' two biggest wins in Trump country, Doug Jones' victory in the Alabama Senate special election in December and Lamb's win in the Pennsylvania congressional race last week, saw candidates who staked out centrist positions that broke from the more progressive wings of the national party.
"I think the fact that Conor Lamb won does show that we need to have candidates that fit the district. It's very important," Lipinski said.
But there are two key differences. Those candidates ran in deep red regions, whereas Lipinski is up for re-election in a district Clinton won by 15 percentage points in a rapidly diversifying region of one of the nation's most Democratic cities.
And unlike Jones and Lamb, Lipinski opposes abortion rights, a position much of the Democratic base is unwilling to tolerate from one of its own.
He voted to block Planned Parenthood from receiving government dollars and was the only Illinois Democrat to oppose Obamacare. He has sponsored 54 bills that Planned Parenthood listed as attacks on women's health.
The anti-abortion group Susan B. Anthony List has taken the unusual step of campaigning for a Democratic lawmaker. But critically, with competitive GOP primaries on Tuesday's docket as well, the group isn't encouraging Republicans to cross over into the Democratic primary to vote for Lipinski.
Lipinski also voted against the DREAM Act, though he now says he opposes repealing Obamacare and wants Dreamers on a path to legal status.
Planned Parenthood, NARAL Pro-Choice America, EMILY's List, the Human Rights Campaign, MoveOn.org and the SEIU are among the progressive activist groups that have pointed to Lipinski's conservative record in backing Newman's challenge.
"We do not have to compromise on protecting women's health to win back the House or Senate," New York Sen. Kirsten Gillibrand, another Newman supporter, told CNN in a statement.
The debate over whether to tolerate anti-abortion candidates has roiled the Democratic Party for months. Last year, Democratic National Committee Chairman Tom Perez said there was no room for such candidates. Later, House Minority Leader Nancy Pelosi, D-California, rebuked him.
Lipinski, meanwhile, is casting Tuesday's election as an opportunity to reverse the party's mistakes that led to Trump's presidency.
"We should focus on those issues that unite all Democrats. Focus on the economic issues," Lipinski said. "That's why we lost the presidential race last time, because middle-class families didn't see us as having that focus that Donald Trump claimed that he did."
"Democrats cannot make that mistake again," he added.
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