Comedian-turned-politician Al Franken used his first campaign event Thursday to proclaim his support for universal health coverage.

Franken, who a day earlier made official his Democratic bid for the seat now held by incumbent Republican Sen. Norm Coleman, toured the Uptown Community Clinic in Minneapolis, where volunteer doctors and nurses treat uninsured patients.

Franken said the large number of uninsured people in the country end up costing government much more than if they were to have some form of insurance.

"I don't think it will cost us any more. I think it will be cheaper," Franken said. "Every other advanced country in the world has universal coverage and they all spend less than we do on health care."

Franken said he hasn't yet formulated a specific plan for universal coverage, but said a good first step would be extending Medicare coverage to all uninsured children.

Franken's emphasis Thursday on weighty policy issues reflected his vow a day earlier to make sure voters take his candidacy seriously, despite his background as a comic performer on "Saturday Night Live."

"I want you to know: Nothing means more to me than making government work better for the working families of this state, and over the next 20 months, I look forward to proving to you that I take these issues seriously," Franken said in his Web message.

Franken's candidacy will test whether Minnesotans are in the mood for another celebrity-turned-politician, after the 1999-2003 governorship of former pro wrestler Jesse Ventura. Ventura's fame and occasionally outrageous behavior regularly brought national attention to the state but wore on the patience of many Minnesotans.

Coleman is viewed as vulnerable because of a Democratic resurgence in Minnesota and President Bush's unpopularity. But his proven skills as a campaigner and fundraiser make him a formidable opponent.

Minnesota Republican Party Chairman Ron Carey issued a statement Wednesday saying Franken offers "nothing but polarization and vitriolic personal attacks."

Franken, 55, was born in New York City but grew up in the Minneapolis suburb of St. Louis Park. He graduated from Harvard University in 1973, and in 1975 joined the writing staff of "Saturday Night Live" during its first season. He soon began appearing in sketches and remained a fixture on the show well into the 1990s.

In 1996, Franken took his career in a political direction when he wrote "Rush Limbaugh Is A Big Fat Idiot and Other Observations," a broadside against the conservative radio host and other figures on the right. He's since published several other books critical of Republicans.

In his latest book, "The Truth (with jokes)," Franken criticized Coleman for his leadership of the Permanent Subcommittee on Investigations, saying Coleman had not held a single hearing on Iraq war corruption.

In 2005, Franken and his wife moved back to the Twin Cities, which was widely interpreted as laying the groundwork for a campaign. He planned to make his first public appearance as a candidate Thursday at a Minneapolis clinic.