Despite voting democratic in the past five presidential elections and 13 of the past 15 U.S. Senate elections, Wisconsin is far from a safe 'blue' state for democratic candidates for governor—especially incumbent Jim Doyle. Democrats have not fared well in gubernatorial elections in the Badger state in recent years, garnering more than 46% of the vote only once in the seven such elections since 1978.
Doyle himself only narrowly won the state's open seat in 2002, beating Republican Scott McCallum by 3.7 points thanks in large part to the strong showing by Libertarian candidate Ed (brother of former governor Tommy) Thompson—who won 10.5% of the vote. Having a second, legitimate right of center candidate on the ballot in that election splintered the conservative vote, allowing Doyle to eke out a plurality vote victory.
This time around, however, the shoe is on the other foot. There is only one third party candidate on the ballot, and this time it comes from Doyle's left: Wisconsin Green Party candidate Nelson Eisman. If the race between Doyle and GOP challenger Mark Green is close (and it is—Doyle has failed to garner a level of support of 50% in any of 12 polls conducted by six pollsters since November 2005), Doyle will need to win over a majority of independent voters as well as protect his left-wing base.
If Eisman's candidacy gains any traction Doyle may be forced to continuously carve out his stance on hot-button referenda issues like bringing back the death penalty to Wisconsin and defining marriage. If Doyle doesn't back these referenda he risks losing votes from the public on issues that enjoy majority-status support. If he does back the amendments, his more liberal supporters might flock in greater number to Eisman.
In a race projected to be as close as the Doyle-Green matchup, a pull to the left on Doyle's candidacy by the Eisman campaign could signal big trouble for the sitting governor.