Politics & Policy

Colorado’s U.S. Senate Battle Map

A map of the 2002 U.S. Senate results, when incumbent Republican Sen. Wayne Allard (R) won reelection over Tom Strickland (D) in a rematch of their 1996 campaign.

A map of the 2004 U.S. Senate results, when Sen. Ben “Nighthorse” Campbell (R) retired, and Ken Salazar (D) defeated Pete Coors (R).

A map of the 2008 U.S. Senate results, when Rep. Mark Udall (D) defeated former Rep. Bob Schaffer (R), following Sen. Allard’s retirement.

Partisan change map (2002-2008):

In this map, the counties marked red (R) and blue (D) are reliably partisan–they have not changed parties since the 2002 U.S. Senate election. The counties marked in green have changed from Republican to Democratic in either the 2004 or 2008 election, and the counties marked in purple voted Republican in 2002, for the Democrat in 2004, and for the Republican again in 2008.

Posted below are the turnout rates for the last two midterm elections in Colorado. The turnout rates by county are calculated using the number of votes submitted for that race per county divided into the number of “active” voters registered. In 2002, the midterm featured the U.S. Senate race between Allard and Strickland, while the most recent midterm election in 2006 uses turnout rates for the gubernatorial contest, as there was no Senate race in Colorado that year:


In the 2008 U.S. Senate election, 83.5 percent of votes cast came from these 11 counties, only one of which is geographically separate from the Fort Collins-Denver-Pueblo “Front Range” (2,021,763/2,422,236):

Of the 11 counties, Republicans have traditionally dominated in (from north to south) Weld, Douglas, El Paso and Mesa counties. Democrats have strongholds in Boulder, Adams, Denver, and Pueblo counties. A quick glance at the partisan swing map shows the three “green” counties–Larimer, Jefferson, and Arapahoe–that have gone from Republicans to Democrats and handed them victories on the state level in the U.S. Senate race twice (2004, 2008) and in the House races in 2006 (CO-7, Rep. Ed Perlmutter, Jefferson) and 2008 (CO-4, Rep. Betsy Markey, Larimer).

In the most recent voter returns from the Colorado Secretary of State’s office, Republicans are holding partisan leads (not including the unaffiliated votes) in these three key “swing” or “battleground” districts.


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