Liberal Democrats have used language like "horrible," "shameful" and "one of the worst" to describe one of their own members of Congress, the moderate, anti-abortion Rep. Dan Lipinski, NBC News reported.
The suburban Chicago Democrat is facing a challenge in Tuesday's congressional primary from Marie Newman, a nonprofit executive who has lined up endorsements from Planned Parenthood, MoveOn.org, Indivisible, Sen. Bernie Sanders, I-Vt., and well-known former advisers to Barack Obama, among others.
Democratic centrists, including the Blue Dog Coalition, support Lipinski.
"I've done 25 or 30 races over the years, and I've never seen a party turn away from a lawmaker like this," Thom Serafin, a former Democratic consultant who is now an independent political analyst, told NBC News.
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Lipinski voted against the Affordable Care Act and declined to endorse Obama's re-election in 2012. A pro-Lipinski mailer featured Obama's image, infuriating Obama administration alums.
The district is considered safe for Democrats in the general election.