Emboldened by the scale of Democratic victories in the midterms, a small group of liberals is trying to blow up a carefully negotiated bipartisan agreement that would make it easier to build in America. Failure to pass this compromise during the lame-duck session would send a loud message that the incoming Democratic majorities aren't as serious about affordability as candidates said they were on the stump. And a deal this good for the economy is unlikely to materialize in the next Congress, which is why unions for the building trades and electricians are fighting to get it done.