FILE - ME Sara Gideon, Susan Collins

Maine House Speaker Sara Gideon (left) and U.S. Sen. Susan Collins, R-Maine.

The potential race between Maine House Speaker Sara Gideon and U.S. Sen. Susan Collins is already heating up even before Gideon has won a primary.

Gideon, a Democrat, recently announced her intention to run for the Senate, challenging fourth-term Republican Collins. The Cook Political Report this week called the election a “toss-up,” in contrast to a Gravis poll conducted in June that showed Collins 14 points ahead of Gideon.

With more than a year still to go before voters weigh in, accusations against both candidates are already flying. The Democratic Senatorial Campaign Committee this week issued a news release arguing that Collins’ support had dwindled since supporting a confirmation vote for Supreme Court Justice Brett Kavanaugh.

Collins in July defended casting her decision, telling The New York Times, “I do not regret my vote."

Meanwhile, a series of ads run on Gideon's behalf attracted the ire of Maine Republicans. Maine GOP chairperson Demi Kouzounas condemned Gideon and her former aides for what she called false information included in campaign advertisements.

“[Gideon] has already been caught illegally funneling corporate contributions into federal elections, and now she is silent while her former aides and allies run a million-dollar scam trying to trick Maine's elderly,” said Kouzounas said in a news release. “If Sara Gideon’s dark money supporters don’t think she can win without this scare-and-scam campaign of lies and Sara won’t speak out for the truth, she isn’t worthy of her current seat, let alone a place representing Maine in Washington D.C."