A Smart Politics study of the 22 U.S. Senate races held in the Gopher State since the union of the Democratic and Farmer-Labor parties in 1944 finds Senate contests held during presidential election years to be less competitive than those held in off years.

Since 1944, there have been 10 elections in which Presidential and U.S. Senate races were on the ballot in Minnesota (1948, 1952, 1960, 1964, 1972, 1976, 1984, 1988, 1996, 2000). The average margin of victory in those Senate races has been a steep 17.3 points. The presidential contests during those years were far more competitive, with an average victory margin of 10.2 points.

In non-presidential election years, the margin of victory in Senate races drops 31 percent to 12.0 points. In fact, four of the last five Senate races in off years have been decided by 6 points or less: Dave Durenberger’s 6-point win in 1982, Paul Wellstone’s 2.6-point win in 1990, Rod Grams’ 5-point win in 1994, and Norm Coleman’s 2.2-point win in 2002. The only recent blowout was Amy Klobuchar’s 20.2-point victory in 2006.

However, despite the overall historical picture of non-competitive Senate races in presidential election years, Minnesota Senate races have been seeing smaller and smaller victory margins in recent years when the presidential ticket is also on the ballot.

· In 1976, Hubert H. Humphrey won his seat by 42.5 points.
· In 1984, Rudy Boschwitz won his second term by 16.8 points.
· In 1988, Dave Durenberger won his second term by 15.3 points.
· In 1996, Paul Wellstone won re-election by 9.0 points.
· In 2000, Mark Dayton unseated Rod Grams by a 5.5-point margin.

The 2008 matchup between Norm Coleman, Al Franken, and Dean Barkley appears to be continuing this trend of increased competitiveness: four of the last five polls conducted during the past month show the race within 4 points between Coleman and Franken.