HELENA — Negative political ads already are oozing out of our television sets to attack Montana’s two major U.S. Senate candidates.

We know these ads are back when we see the slow-motion videos of the targeted candidate, the shadowy backgrounds, the ominous-sounding narrators and the horror-movie soundtracks.

And we haven’t seen anything yet. Over the campaign’s final six weeks, we will be hit by ads so nasty they will make the current spots look like valentines.

Expect an onslaught of these vile ads and snarky direct mail pieces that will accuse Republican U.S. Sen. Conrad Burns and his Democratic opponent, Jon Tester, of everything under the sun. These ads often contain a grain of truth and little more, but sometimes they are accurate.

The competing campaigns, the parties’ senatorial campaign committees and mysterious 527 groups will be spend hundreds of thousands of dollars on the airwaves to slice, dice and puree whichever candidate they oppose.

So if everyone hates negative ads so much, why do campaigns still use them?

“They use them because they work,” said Craig Wilson, a political science professor at Montana State University-Billings. “This year’s Senate race is running true to form. The closer to the election, the more negative it gets.”

Negative campaigning “is about as old as campaigning,” he said. More than 200 years ago, scurrilous pamphlets were the weapon of choice to slime political opponents.

In Montana, negative ads are aimed at the 20 percent of the electorate classified as independent or persuadable voters, Wilson said. They also help cement the support of a candidate’s own supporters.

Jerry Calvert, a political science professor at Montana State University, said these ads work because they grab voters’ attention.

“They appeal to the gut through visual and auditory cues,” he said. “Research suggests that negative ads at a minimum reinforce partisans. Second, negative ads contain information delivered in seconds, information not found easily in your local newspapers and certainly not on your local television and radio news.

This kind of advertising tends to turn off the less partisan, more independent and less-involved sector of the electorate, he said.

“It creates a self-fulfilling wish that all politicians lie, all are crooks, etc. and thus can have the effect of driving down the turnout by driving away the less political, less committed part of the electorate,” Calvert said.

Larry Sabato, director of the Center for Politics at the University of Virginia, said negative advertising works if it’s well done.

“Like with most advertising, it’s surprising how few are well done and make a difference,” Sabato said. “There are loads that attract the attention of the press and the political cognoscenti. There are surprisingly few that have an impact. People are hardened.”

The most effective negative ads, he said, are those that actually use credible footage of the opponent.

“It’s hard to refute what a candidate actually said,” Sabato said, citing Burns’ gaffes.

So what are besieged voters to do? Here are a few self-defense tips:

n Attend, watch or listen to candidate debates. TV and radio stations will air most of them. Size up the candidates for yourself.

n Watch to see if the candidates will campaign in your town. Burns posts his daily schedule on is Web site, while Tester lists some events.

n Check out the candidates’ respective campaign Web sites and see where they stand on issues. Burns’ Web site is at: http://www.conradburns.

com/.

Tester’s is at: http://www.testerforsenate.

com/.

n Check out the voting scorecards on the candidates issued by a host of interest groups ranging from the Chamber of Commerce to the League of Conservation. Look at these groups’ Web sites or call them.

n Use the Web site known Project Vote Smart, an invaluable national nonpartisan, nonprofit research group based in Phillipsburg. It’s packed with information on the Senate race as well as legislative races. Burns completed its National Political Awareness Test, but Tester, inexplicably, refused. Its Web site is: www.vote-smart,org.

n Track the bucks. Look at analysis of which economic interests and lobbying groups have donated the most money to each campaign. You then can pretty much predict how each will vote on key issues. Two very reputable national nonpartisan groups offer campaign finance information on their Web sites. They are the Center for Responsive Politics at www.opensecrets.org and PoliticalMoneyLine at www.fecinfo.com. To learn who donated to Tester’s two state Senate races, check out the outstanding Web site of the Institute on Money in State Politics, a national, nonpartisan nonprofit group based in Helena, at: www.followthemoney.org.

n Watch the Web logs — or blogs — on the Internet. These are some keen, often highly partisan, observers of the Montana political scene who offer unique insights. For a list of some of Montana’s best, check out the list on Billings Gazette reporter Ed Kemmick’s own blog, City Lights, at http://www.billingsgazette.

net/h/blogs/citylights/.

n Check out the Ad Watches in your local newspapers if they do them. These stories parse the details from respective ads to determine if they are true.

Multi-million dollar, negative election campaigns are here to stay, but that doesn’t mean voters are helpless.

“My advice to voters, as always, is buyer beware,” said Sabato, a national expert. “It isn’t just at fire sales, It’s also in political campaigns.”

Chuck Johnson is chief of the Lee Newspapers State Bureau in Helena. He can be reached at (800) 525-4920 or (406) 443-4920. His e-mail address is chuck.johnson@lee.net.