WATERVILLE – With just a few weeks to go before Election Day in 2010, a national group saw an opportunity.

“The Maine state Senate is within distance of changing hands. We see that as an opportunity to flip that body, which is why we’re getting involved there,” declared Adam Temple of the Republican State Leadership Committee in October 2010. That involvement came in the form of a massive wave of negative advertising, which in many cases was later found to contain misleading, or outright false, statements.

Formed in 2002, the GOP leadership committee gained new significance in 2010. The group was devised by Karl Rove and funded by national business and political groups (including the American Justice Partnership, the Michigan-based organization financing most of the 2011 campaign to stop Maine’s return of same-day voter registration). The group spent $400,000 in the final weeks of Maine’s 2010 elections. These expenditures more than quadrupled what the supported candidates had spent on their campaigns to that point.

This was a big surprise. Until 2010, campaigns for the Maine Legislature had been largely local affairs.

However, the U.S. Supreme Court’s decision in the Citizens United case in 2010 gave wealthy political players the gift of unlimited spending, leading national pockets full of money to search for local candy stores. Maine, with our relatively modest media costs, was in effect a row of shiny penny candy.

Did it matter? Many people say they’re not persuaded by campaign ads. But there’s plenty of evidence that advertising is effective when people don’t have strong existing opinions. This is unfortunately an important dynamic in state legislative races.

Political partisans vote for their party’s candidate, but many Mainers are politically unaffiliated and make case-by-case decisions. These voters choose a candidate when they meet them going door to door, or when they listen to the opinion of a well-informed friend, or when they already know the candidate.

However, this familiarity is not so decisive that people can’t be convinced otherwise. When ads come over the radio saying terrible things about the candidate whose hand you happened to shake, you’re willing — and reasonably so — to accept that there might be something important you didn’t know about that person.

What you may not know when you hear those ads is that political advertising isn’t required to be truthful.

Unlike advertising about toothpaste and car insurance, for instance, there’s no regulation preventing political campaigns from lying.

The federal government penalizes commercial advertisers who make false claims. However, because political speech is so strongly protected under the First Amendment, political actors are expected to regulate themselves — and one another.

A major line in defense of truth are the reputations of candidates and campaigns.

In the past, because campaign donors have had to put their reputations on the line when they acknowledged sponsoring advertisements, there was a certain protection against outright falsehoods.

In the post-Citizens United world, this defense is gone. Without requirements for disclosure, campaign donors have no incentive to ensure that the campaign materials they finance reflect well on them.

The Republican State Leadership Committee spent mostly on ads attacking Democratic candidates rather than promoting Republican candidates in 2010. Because the spending was so late and so heavy, Democratic candidates had no effective opportunity to respond.

What was especially remarkable about the revolutionary nature of the RSLC-funded advertising is that two of the five RSLC-supported Senate candidates condemned the advertising the group issued in their races.

That is really telling. Those Republican candidates were absolutely serious about winning, but they wanted to win in a way that was consistent with their values — not by smearing their opponents.

State legislators, after all, tend to be honorable, public-minded folks. That obviously isn’t true of the national PACs that shield the names of their donors and buy deceptive attack ads on Maine’s airwaves.

As we approach another season of anonymous PAC spending with no legal defense in place, it’s a good thing to reach beyond your TV and radio dials for information. Voters should go to public debates and meetings. On the Internet, they should visit www.maine.gov to find out more about their legislator’s voting record.

If we value the integrity of our state elections, we all have to be our own best defense.

Emily Shaw is an assistant professor of political science at Thomas College in Waterville.