Aug 10, 2010 8:18 AM by Bea Karnes, News First 5
Colorado Democratic Sen. Michael Bennet is the latest incumbent senator battling for his job.
Bennet faces former Colorado House speaker Andrew Romanoff in a primary challenge Tuesday marked by the anti-establishment mood seen in every corner of the nation.
Republicans have their own outsider-versus-insider Senate story line. Former Lt. Gov. Jane Norton faces Ken Buck, a rural prosecutor who has criticized Norton as being too cozy with Washington Republicans.
Colorado's primaries are mostly mail-in. Early ballot counts from state officials indicate primary turnout could reach record highs in some counties.