CNN  —  Entering Election Day on Tuesday, the battle for control of the US House of Representatives rests on a knife’s edge, with a historically small universe of competitive races poised to determine the chamber’s majority in the next Congress – an outcome that could have far-reaching consequences for the next president’s agenda. All 435 House seats are on the ballot, with Republicans defending a slim majority and Democrats needing a net gain of four seats to flip control of the chamber. There