Through the media and technological revolutions that have transformed electoral politics in recent decades some things have stayed reassuringly stable.

When it comes to winning a seat in the Maine Legislature, the prize typically has gone to the candidate who worked the hardest, knocked on the most doors, ate at the most bean suppers or stood the longest out in the rain outside a shopping center.

With the advent of the Maine Clean Elections system, candidates were even more free to engage in retail politics, and at least one candidate in most legislative races relied on public financing.

This year, however, an influx of interest group money may change that.

This is shaping up as the most expensive legislative race on record, with hundreds of thousands of dollars being dumped into political action committees that campaign for or against candidates outside the formal campaign structures.

These independent expenditures trigger matching funds for the 80 percent of contenders who are publicly financed, and even clean candidates are looking to spend.

Among the sources of the campaign money is the Republican State Leadership Committee, which has dropped $400,000 on five state Senate races in Maine, hoping to tip the balance in the Maine Senate.

If this is successful, look for it to be repeated every election cycle in the future. For a group with a national donor base, Maine, with only two major televsion markets, is a cheap place to make an impact. Groups looking to change social or environmental policy could see Maine as place to establish a beachhead.

The outside expenditures also put pressure on the Clean Elections program, by triggering matching funds for contenders.

In the end, however, it may be that voters won’t respond to the deluge of political advertising, and keep voting for the candidate who came to their doors or shook their hands.