Perhaps the hottest congressional campaign in America is right here in Maine.

The 2nd District showdown between U.S. Rep. Bruce Poliquin, a first-term Republican, and Democratic challenger Emily Cain is one of the most expensive in the nation and is filling the airwaves with more advertising than any other congressional race in the land ahead of the Nov. 8 election.

The tight battle between the two has already attracted more than $12 million from those seeking to influence the outcome — the most costly contest in the state’s history. That’s led to 21 percent more television advertisements bombarding viewers in Maine than in any other U.S. House race.

At the center of all that cash and attention are Poliquin and Cain; Cain lost to Poliquin two years ago and hopes for better luck in a presidential year rematch.

“If you’re tired of big money in politics and on your TV, there’s only one solution: Vote,” Cain said Monday.

The hitch, though, is which candidate to vote for.

An advertising report by the Wesleyan Media Project found that Maine television stations aired 9,327 commercials related to their congressional battle between Sept. 16 and Oct. 13 — for an average of 333 daily.

The study took into account ads bought by outside interest groups, not just the ones placed by Cain and Poliquin.

Cain alone, though, has run more ads for her campaign than anyone running for Congress this year except Republican Ryan Zinke in Montana.

Both Maine candidates raised about $3 million through early October, with Poliquin holding a slight lead.

In addition to party-connected spending, many independent political groups have poured money into the district. They’re aiming to capture the seat for their favored candidate but some are also interested in bolstering the fortunes of the two presidential contenders.

The district is unusual in that whichever presidential candidate garners the most votes within it will come away with an electoral vote that could make a difference in the outcome. Polls show that both the congressional and presidential tallies in the district are likely to be close.

The total amount spent on congressional ads in the 2nd District during the time studied came to $2.8 million, which is among the highest in the land. Maine’s media markets are cheaper than many others across the country.

The low cost of airing commercials in Maine has helped to keep the number of ads particularly high. Only three other districts in America saw more than 5,000 commercials during the time frame eyed by the Wesleyan study.

It also found that Democrats are well ahead in terms of the number of ads benefiting Cain rather than Poliquin.

According to the Wesleyan study, Cain had 2,500 more ads favoring her than Poliquin had on his side of the column.

There’s only one district in the country where Democrats have more lopsided advantage on the airwaves, an open seat in upstate New York.

The candidates, not surprisingly, have opposing thoughts about where all the money is coming from.

Cain said, “The simple truth is that Bruce Poliquin’s Wall Street backers are pouring money into this race because they know that he votes their way and I won’t.”

House Minority Leader Nancy Pelosi, a California Democrat, “is pouring millions of dollars into Maine’s 2nd Congressional District in order to regain control of the House of Representatives,” said Michael Byerly, Poliquin’s campaign spokesman.

“Emily Cain would be a rubber stamp of approval for Nancy Pelosi’s extreme liberal agenda,” he said.

“We need more transparency and new rules to limit big money in politics, but Congressman Poliquin, one of the top recipients of Wall Street money in Congress, opposes repealing Citizens United and has voted to keep donors secret, potentially allowing illegal and foreign money to influence our elections,” Cain said.

Cain’s campaign aired just shy of 3,700 ads in the study period compared to 1,463 by Poliquin, though he has actually raised a little more money overall.

The rest of the 2nd District ads were paid for by party committees and independent political action committees.

The National Republican Congressional Campaign Committee took out almost 2,000 ads, while its Democratic counterpart bought 749 commercials.

Also shelling out for more than 300 ads apiece were the House Majority PAC, the Vote Vets Action Fund and the NEA Advocacy Fund.

The Wesleyan study said it received data on the ads from Kantar Media/CMAG and considered commercials that aired on broadcast television, national networks and national cable. There may well be other ads that were not counted.

An advertising report by the Wesleyan Media Project found that Maine television stations aired 9,327 commercials related to Poliquin and Cain’s congressional battle between Sept. 16 and Oct. 13 — for an average of 333 daily.