When a handful of anti-abortion Democrats were the last remaining obstacle to Obamacare’s passage, most were swayed by a last-minute compromise. Rep. Dan Lipinski, D-Ill., held firm and voted against his party’s signature healthcare law.

Now that Democrats are eyeing their first House majority since that Congress, some liberals hope Lipinski will not be part of it. A broad coalition of progressive groups is backing Lipinski’s challenger, businesswoman and nonprofit executive Marie Newman, in one of the most important primaries to watch this year.