Groups that can shell out an unlimited amount of money to influence Maine’s gubernatorial and legislative races have blown past the previous spending record, plowing $4.6 million into the 2014 campaigns with 40 days remaining before the Nov. 4 election and most of the expensive television ads still to come.

The governor’s race alone has topped $4.2 million in spending. That surpasses the record total of $4 million paid in 2010 by the groups, which operate independently of candidates’ committees but invest money to affect a specific outcome, and later to implement laws or policies that can benefit the organizations.

While the largest expenditures continue to be on television advertising, reports from the Maine Commission on Governmental Ethics and Election Practices show that money is also flowing into mailers, telephone campaigns and door-to-door canvassing operations.

The biggest spenders are the Republican Governors Association, which has spent $1.9 million to date backing Gov. Paul LePage, and MaineForward, a progressive PAC funded by national labor and conservation groups and the Democratic Governors Association that has spent more than $1 million supporting U.S. Rep. Mike Michaud.

The surrogate groups supporting LePage and Michaud are doing the majority of the negative campaigning with each playing to their constituencies, according to Anthony Corrado, professor of government at Colby College and one of the leading campaign finance experts in the country.

Corrado said Maine is witnessing record spending that will continue through Election Day, particularly in a gubernatorial race that polls show as a close battle between Democrat Michaud and Republican LePage, while independent Eliot Cutler trails a distant third.

“We also see this because of the growth in partisanship in the country now,” he said. “As the divide between Democrats and Republicans has intensified, the stakes of having a Democrat or a Republican – in Congress, the State House or the Legislature – have become much higher.”

The spending in the governor’s race is dominated by groups running television ads either supporting or opposing LePage or Michaud. Political action committees have spent more than $1 million supporting LePage and another $1 million opposing him. Similarly, groups have spent more than $957,000 against Michaud and $1.2 million supporting him.

Cutler has not received any support from independent groups since the spring and has been largely ignored by political action committees, which have spent a combined $700 opposing him. The spending contrast largely reflects Cutler’s position in the latest polls. While his campaign this week released an internal poll showing that his support was increasing, his ascent hasn’t attracted attention from progressive groups, who have an interest in keeping Cutler from eroding Michaud’s base of support.

The spending by progressive PACs has all the hallmarks of a turnout-driven election. Groups like the San Francisco-based NextGen Climate Action Fund ($280,000), the Committee to Rebuild Maine’s Middle Class ($28,000) and the AFL-CIO affiliated Workers’ Voice ($5,455) have focused almost exclusively on voter contact through phone banking, canvassing and direct mail.

MaineForward has run ads against LePage and supporting Michaud. The group posted more than $302,000 in spending Friday, including a $46,700 expenditure for direct mail and $31,000 on web-targeted ads.

Maine Forward is also receiving money support from the League of Conservation Voters, whose Maine operation has spent more than $500,000, much of it on television ads and mailers.

The Washington D.C.-based Republican Governors Association backing LePage is primarily focusing on television ads.

Corrado said Mainers should brace for continued record spending. While it’s unclear how the dollars pumped into the race will influence voters, the impacts could linger after Election Day.

“One of the concerns among those increasingly alarmed by these groups is that they end up influencing voter behavior,” said Corrado, adding that there could be policy implications.

“We’re already seeing that on Capitol Hill,” he said. “When a legislator is thinking about a vote, he or she may be thinking, ‘If I vote one way or the other will that result in a group spending $100,000 or $200,000 against me in my next election campaign?’ I like to compare it to the shot across the bow. It could happen to you.”