Both redistricting (ie, apolitically drawn districts) and non-partisan primaries are intended to benefit more moderate politicians, who may pride themselves on finding compromises and reaching out to foes.

ECONOMIST: California: Not quite Greek, but still weak | The

For example, even in the midst of gridlock in 2012, Democrat Barbara Boxer of California and Republican Jim Inhofe of Oklahoma reached agreement on a major transportation bill, and Democrat Tom Harkin of Iowa and Republican Mike Enzi of Wyoming forged compromises to produce a far-reaching food safety legislation.

CNN: Senate holds key to fixing Washington