On the surface, there’s nothing unusual about Mary Liz Holberg’s decision to retire from the Minnesota House after 16 years of service. Sixteen years is a long time in any legislative body, and Holberg’s Republicans are in the minority in the House -- and likely to stay there for now.

What’s interesting is Holberg’s choice of a career move. She is running to be a commissioner in her home county of Dakota, located on the southern outskirts of metropolitan Minneapolis. If she wins, she will join another former legislator, Republican Chris Gerlach, who left the state Senate to become a Dakota County commissioner in 2013.

Dakota County is a nice place, but its local government is not the only one in Minnesota that has attracted the attention of state legislators. Some excellent research by Patrick Condon of the Minneapolis Star Tribune recently turned up five legislators or former legislators in Minnesota who are running for county office this year. That’s in addition to several others who have made the move successfully in the recent past.

For some of them, the explanation lies no further than the difference between a legislative paycheck and a county paycheck. As a state representative serving in a body that can meet close to full time for almost half the year, Holberg earns a base salary of about $31,000. If she makes it onto the Dakota board, she will receive more than $70,000 a year.

Only 15 of Minnesota’s 87 counties pay commissioners more than state legislators make, but a few of these, especially in the Minneapolis-St. Paul area, pay lots more. The champion, as Condon reports, is Hennepin County, which contains the city of Minneapolis itself. Commissioners in Hennepin make close to $100,000 a year. Four of the seven commissioners currently serving there left the legislature to move into their present line of work.

If you’re wondering whether this flight to the counties is likely to ripen into a national trend, the answer is almost certainly not. The financial incentive doesn’t exist. County governments that pay more than legislatures are rare virtually everywhere. Minnesota is an anomaly, and even then it’s one confined to just a small part of the state. But it’s an anomaly that provokes some interesting questions about incentives and status in political institutions all over the country.

The truth is that the makeup of any state legislature has always been less a function of voter demand than of the costs and incentives that lead some people to seek the office and others to stay away. For many states in America in the 20th century, serving in a legislature offered a slice of political power and a concentrated few weeks of social networking, usually in a state capital relatively far from home. Money wasn’t an incentive because the job hardly paid anything. But time wasn’t much of a disincentive because the sessions frequently were over by springtime.

As a result, the job attracted local civic leaders­ -- lawyers, farmers, insurance brokers -- who could afford to spend concentrated periods away from work and who took it as an honor that their fellow citizens desired their services. In the Northern states, these tended to be middle-aged, middle-class white Protestant Republicans. In the South, they were essentially the same people, except that they were Democrats. The bulk of them came from small towns and rural areas, because the districts were gerrymandered -- drawn with unequal populations for rural advantage.

All of that began to change in the 1960s and even more in the 1970s. One reason was the end of population gerrymandering, as decreed by the U.S. Supreme Court. But an even more important reason was the movement to reform and professionalize legislatures, promoted and largely financed by the Ford Foundation.

Ford believed that state governments were too antiquated and too secretive to play the role required of them in a changing political system. The foundation supported annual legislative sessions, enhanced staffing and technical capacity, and far greater transparency in communicating with the public. The reformers also called for higher salaries to reflect the new level of responsibility that state legislators should be taking on.

By 1980, many of the largest states had essentially bought into the reform model. Legislatures in California, Illinois, New York, Pennsylvania and a handful of other places were meeting through most of the year, hiring professional staff to manage much of the workload and ramping up legislators’ pay significantly.

A few states, most of them small ones, rejected the reform model almost entirely, continuing to run short sessions with minimal staffing and old-fashioned pay scales. To this day, senators and representatives in New Hampshire receive $200 as compensation for two years of service, with no per diem included.

Left in between were mid-sized states, Minnesota among them, which chose to adopt most of the reform recommendations but declined to make corresponding adjustments in their members’ pay. By the 1980s, most of these states were asking their members to give up substantial portions of their year to legislative sessions and post-session business, often making it difficult for them to hold private-sector jobs and paying them less than even the lower ranks of professional workers.

The result was that the old incentive structure disappeared. Service in a heavy-duty, low-paying institution ceased to be attractive to the Main Street business contingent that had signed up for it in earlier years. Instead, legislative careers began to attract a new cohort: the independently wealthy; citizen activists -- mostly women -- who were not the breadwinners in their families; and people engaged in low-paying professional jobs who could run without taking a significant pay cut.

If the reformed legislature imposed a financial sacrifice among its participants in many states, it also offered them policymaking opportunities that had not existed in the old days. Most of the new members elected in the early reform years of the 1970s and 1980s were self-starters. They weren’t eased into political service by local power brokers, as their predecessors had been. When they arrived in office, most of them wanted to make a splash right away, and a remarkable number of them did. Minnesota, Wisconsin and progressive-leaning states around the country enacted long lists of legislative initiatives in these years. They imposed new regulations on corporate business and dramatically expanded the social service benefits available to lower-income citizens. Being a legislator in the reform years meant accepting a financial squeeze, but for the politically ambitious, it could be a lot of fun.

But the reform era slowly petered out in the 1990s. States’ legislative leaders began reclaiming the influence that they had lost over the preceding decades. They raised leadership PAC funds to recruit favored candidates in competitive districts, and maintained an influence over these new recruits once the legislative sessions convened. They began showing less tolerance for the mavericks and individualists who had acquired a substantial amount of power in the early reform years.

Perhaps even more important, legislative politics started to take on a sharper partisan cast than had been the case before.

Republicans, who had lagged far behind Democrats in attracting top quality candidates, became much more effective at generating them. The key event in this transition was the election of 1994, in which Republicans at the state level saw their congressional counterparts sweep to control over both the U.S. House and the Senate. Watching what GOP strategist Newt Gingrich had accomplished with hard-nosed partisan attack politics in Washington, Republican legislative leaders in the states began to see the advantages of a less collegial approach. And they presided over rank-and-file caucuses that were perfectly eager to go along.

The simplest way to explain state legislative politics in the last two decades is to say it has become more like congressional politics. As in Washington, candidates run in districts much more skewed by party and ideology than in the past, with incumbents of both parties rewarded more for catering to activists at the end of the political spectrum than to seeking out a middle ground.

Legislators vote more frequently in lockstep agreement with their party majorities than they used to, with the opportunities for policy freelancing by individuals few and far between. And as in Washington, state legislators develop personal relationships almost exclusively with colleagues on their own side of the aisle, with few of the opportunities for off-hours bipartisanship that were a hallmark of legislative life in the pre-reform era.

So it shouldn’t be a surprise if significant numbers of legislators in heavily partisan states come to feel that there are more enjoyable and less stressful ways they might be spending their time. In Wisconsin, which has seen almost nonstop partisan rancor since Republicans took full control four years ago, there has been a remarkable exodus of senior legislators in the current election cycle. Milwaukee’s Journal Sentinel reported recently that when the state’s next legislative session begins in January, 54 of the 99 members of the assembly would be people elected since 2010. As of a couple of months ago, more than two dozen members of the assembly had announced plans to retire in 2014.

Maybe that’s unrelated to the unprecedented bitterness of legislative life in Madison during the past three and a half years. Personally I don’t think so.

Things haven’t been quite as rough across the border in Minnesota, but they haven’t been pleasant, either. In 2011, the state endured a three-week government shutdown as a result of a budget dispute between Democratic Gov. Mark Dayton and the then-Republican legislative majority. Scars from that affair have been slow to heal. And with Democrats having taken full control of the legislature and governorship, veteran Republicans like Mary Liz Holberg have been reduced to mostly glorified spectator roles.

In a situation like that, a job dealing with the minutiae of county government can start to look pretty attractive. And when the county job brings with it a nice raise in pay, the opportunity can be too appealing to resist.