HARTFORD (AP) — Connecticut voters were inundated with political mailers and advertising this year, much of it courtesy of vaguely named groups such as Change Connecticut and Connecticut Values.

A review by The Associated Press of state election records shows roughly 40 entities, including political action committees formed by unions, real estate agents, national party affiliates and issue organizations like Planned Parenthood, spent at least $12.5 million on what are known as "independent expenditures" on Connecticut's 2018 state elections.

While there was a large concentration of outside money spent on the 2018 governor's race — just like in 2014 — this year's election highlighted a growing interest among groups to try to influence partisan control of Connecticut's General Assembly. National Republicans saw an opportunity to take control of another state legislature, given how the Democratic majority in Connecticut has shrunk in recent elections amid voter frustration over the state's budget challenges.

"You look at a state like Connecticut and say, 'Well, why are we there?'" said David James, spokesman for the Republican State Leadership Committee, which contributed more than $1.8 million to the Change Connecticut PAC, an entity that worked to help GOP legislative candidates. "We're there because we're on the march and we're looking for that room to expand, to play deep into Democrat territory."

Ultimately, Democrats managed to expand their ranks this year. They will hold a 23-13 majority in the state Senate and a 92-59 majority in the House of Representatives when the legislature reconvenes in January. But that doesn't mean the leadership committee, an arm of the national Republicans, is giving up. With the GOP controlling the majority of state legislatures in the country after Election Day, the party still sees opportunity in traditionally Democratic states.

"At the state level, Republicans have the Democrats' backs against the wall in many areas," James said, noting close races like Connecticut's 17th state Senate district, where Republican state Sen. George Logan, of Ansonia, managed to win by 85 votes. "And if we're playing into states like Connecticut and Maryland and other places, this is where we look to grow."

Records show political action committees supporting Democratic legislative candidates spent large sums, as well, this year. The Democratic Legislative Campaign Committee was a major funder to the Connecticut Values PAC, which raised approximately $520,000 to support mostly Democratic General Assembly candidates.

The Service Employees International Union spent more than $1 million on everything from voter canvassing to digital ads affecting Democrats in legislative and governor races. And Alice Walton, the daughter of Walmart founder Sam Walton, contributed to the Build CT PAC, which raised $132,606 to support Democratic legislative candidates.

The biggest outside spender in the governor's race was the Republican Governors Association, which spent about $7.4 million to support GOP candidate Bob Stefanowski, who lost to Democratic Gov-elect Ned Lamont.

Cheri Quickmire, executive director of Common Cause in Connecticut, said she is concerned by the large amount of outside money continually being spent in Connecticut, one of several states with a voluntary public campaign financing system.

Common Cause recently issued a joint report on independent expenditures with the Connecticut Citizen Action Group. It warns how special interest spending "drowns out the voices of Connecticut citizens and candidates" and "undermines the goals of Connecticut's strong campaign finance laws."

"These various groups have learned that they can create these super PACs where they can in many ways disguise where the money is coming from," said Quickmire, who plans to push for legislation to beef up reporting requirements. She blames much of the outside money on the 2010 U.S. Supreme Court Citizens United decision that allowed corporations, unions, lobbying organizations and wealthy individuals to spend unlimited amounts of money influencing campaigns. They are not allowed, however, to coordinate such activities with the candidates.

This same debate happened after outside interests spent roughly $17.4 million in 2014 — most of it on that year's close gubernatorial election — but there was not enough support for new legislation. Roughly $1.4 million of outside money was spent in 2016 to mostly influence legislative races.

Democratic state Sen. Mae Flexer, of Danielson, a chairman of the legislature's elections committee, said she worries the continuing flow of outside money into Connecticut's elections will undermine the Citizens Election Fund, the state's public financing system.

A federal appeals court in 2010 struck down part of the program that provided extra funding to publicly funded candidates who are outspent by well-financed opponents or face large amounts of targeted outside spending. Flexer faced such a situation two years ago, when an outside group paid for a slew of negative social media and mailers.

"It's really scary. And in the throes of it, you can't help but think, 'Oh, I should have just gone out and raised money the old-fashioned way,'" said Flexer, who plans to push for reforms next session.

If there's going to be a debate over Connecticut's campaign finance laws, Senate Republican Leader Len Fasano said, it has to be wide-ranging and address issues like whether Democratic U.S. Sen. Chris Murphy should have been allowed to transfer $320,000 from his campaign committee to help the Connecticut Democratic Party with mostly get-out-the-vote efforts.

But in the meantime, Fasano doesn't see much changing, given the federal high court ruling.

"Citizens United is the law of the land and people have the right to advocate as long as they don't coordinate with other folks," he said. "Maybe that's going to change the face of elections from this point forward. It's going to be big money. We're just going to have to face that reality."