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The major battleground this election season may be the U.S. Congress, where the Democrats may lose control of the Senate for the first time since 2007, but that doesn't mean that the Republican Party is neglecting the governor's races.

Contentious ads in two states with close races began airing on Tuesday that are stirring up Democratic anger.

The spots are sponsored by the Republican Governors Association, which is headed by New Jersey Gov. Chris Christie. One of them paints the Democratic governor of Colorado, John Hickenlooper, who finds himself in a tight race against former U.S. Rep. Bob Beauprez, as going soft on a convicted killer.

The other suggests that Rep. Mike Michaud, the Democratic hopeful in Maine trying to knock off the incumbent Gov. Paul LePage, would dole out millions in tax dollars to immigrants who have entered the country illegally.

The rollout of the ads come as polls show both Colorado and Maine to be tight races — and the latest finance reports show the Republicans' committee with more than $70 million saved to help GOP candidates.

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    The RGA was already advertising in those races and the new ads will take the place of earlier ones. In Colorado, that means $700,000 in Denver and Colorado Springs will be spent on the ad; in Maine, it's a $500,000 buy in Portland.

    In Colorado, the 30-second ad cites Hickenlooper's suggestion that he might scrap the death sentence of a multiple murderer on death row if he loses his re-election campaign. Hickenlooper already has given the inmate Nathan Dunlap a temporary reprieve from execution as long as he is governor.

    Dunlap was convicted of killing four employees inside an Aurora, Colorado, Chuck E. Cheese after the children's restaurant closed. In the decades since the 1993 killings, advocates have pointed to failures of Dunlap's trial lawyers and a diagnosis of bipolar disorder — developments that raised concerns for Hickenlooper.

    In an interview with CNN, Hickenlooper suggested he could make that reprieve permanent if he loses in November.

    "There are obviously remedies that the governor can do, you know," Hickenlooper told CNN for a documentary. "I could give it a full clemency between Election Day and the end of the year."

    One of the victims' fathers, Bob Crowell, called Hickenlooper a "coward" for the move. The RGA used that assessment in its ads.

    The governor's office said Hickenlooper was dealing in hypotheticals and was discussing legal options that are available to him. His campaign called the ads unfair and driven by politics, not justice.

    "The governor made a decision and he stands by that decision. Nathan Dunlap will die in prison," campaign spokesman Eddie Stern said. "It is a legitimate question whether the state should take a life, and the fact that victims' families have conflicting views on this issue underscores the importance of this discussion."

    Across the country, the RGA also started new ads against Michaud, claiming he would turn Maine into a destination for immigrants who are in the United States illegally.

    Maine, whose population of 1.3 million is about 94 percent white, is home to an estimated 55,000 immigrants and relies heavily on migrant workers for its blueberry harvest every August.

    For months, LePage has hammered Michaud on immigration — in a state almost 2,500 miles from the U.S.-Mexican border. LePage touts his directive that cities and towns not provide welfare benefits to those who can't prove they are living in the country legally.

    In Congress, Michaud supported the 2010 DREAM Act, which would have granted legal status to hundreds of thousands of immigrant students. Michaud also opposed the 2006 Border Security Bill, which would have built a 700-mile fence along the United States' southern border.

    Republicans said Michaud favored immigrants over Maine residents.

    "Do you think Maine's cities and towns should continue to use your tax dollars to pay welfare benefits to illegal immigrants?" the 30-second ad's narrator asks. "Mike Michaud does."

    Michaud's campaign said the RGA is an attack rooted in politics, not facts.

    "It is a distortion of the congressman's record and it's untrue," said David Farmer, a senior adviser to the Michaud campaign.

    LePage is among the most disliked governors facing voters this fall and one of the few chances Democrats have of tipping a governor's office in their favor.

    "They can't improve Paul LePage with positive ads," Farmer said. "Voters here in Maine have a low tolerance here for negativity."

    Michaud's campaign is on the air with two positive ads highlighting the congressman's life story and his work to help New Balance, a New England-based company.

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