"Wouldn't term limits give us a better Legislature?" a member of last Tuesday's audience at Minneapolis Central Library asked former GOP state Sen. George Pillsbury and me as we discussed our book, "The Pillsburys of Minnesota."

Pillsbury said he's always liked the idea. He looked at me expecting that I would agree. I disappointed him.

Term limits deprive the Legislature of institutional memory and loyalty, I said. They makes the Legislature more dependent on staff and interest groups. And they aren't needed in Minnesota, where the average length of a legislators' service has been measured in various ways through the years as being between six and eight years.

The Minnesota Senate has lately provided a case study of what can happen when a big freshman wave hits. Twenty-one of the 37 members of the GOP majority are first-termers or newly back after a hiatus or House service. The same goes for seven of 29 DFLers. (One seat in the Senate is vacant after the death of DFL Sen. Gary Kubly.) The December leadership upheaval in the majority caucus, an atmosphere of rigid staff control that chilled dissent, and a spate of legislation originating with national conservative organizations are all symptoms of a Senate that's too green. Some would put last summer's shutdown on that list as well.

The 2012 post-redistricing election is destined to drain still more experience from the Senate, according to an analysis by Capitol Report last week. When the Senate adjourned for the bieunnium in 2010, its members had clocked 747 cumulative years of service. Today that total is 551 years, and retirements already announced (and more could be coming) will take the total to 431 years at the start of the 2013 Senate session. The median length of Senate service in 2013 could be close to two years.

What's wrong with that? Former House Speaker Margaret Anderson Kelliher nailed it when she told me recently that legislators hit their stride in effectiveness at between six and 14 years of service. A lawmaking body with a disproportionate share of rookies is one prone to stumbling, not striding.