“The Senate hasn’t been so polarized since Reconstruction; the House has not been so divided since around 1900. As measured by laws passed, the current Congress is on track to be among the least productive in our republic’s history. … One of the main causes has not gotten enough attention: the party primary system. … The partisan primary system, which favors more ideologically pure candidates, has contributed to the election of more extreme officeholders and increased political polarization. It has become a menace to governing.”
– New York Democratic Senator Charles Schumer, in End Partisan Primaries, Save America
Schumer makes a strong case that open primaries, such as California adopted in 2010, are needed to reduce polarization and gridlock in American government.