Add in Obama’s low approval rating in the traditionally blue state—43 percent in an April Suffolk University poll —and a Republican nominee, Mike McFadden, seeking to project a non-fiery, problem-solver image, and there is a real test for Franken’s transformation into a low-key workman.

“Al Franken’s gonna have a fight on his hands. I don’t think there’s any doubt about that,” said Larry Jacobs, a political scientist at the University of Minnesota and director of its Center for the Study of Politics and Governance.

For Republicans, he said, “what they want is McFadden to be a passive, pleasant receptacle for anti-Obama votes.”

To protect his advantage, Franken, once a Saturday Night Live star and unabashedly partisan radio host, must build off his quiet record in the Senate to keep the race about him, not Obama.

His ads have touted his results on issues such as workforce training and food safety. His DFL convention video features an interview with a woman who touts the “seriousness” he brings to his job as senator.