Independent Angus KingAngus KingAngus King: Russia probe ‘a duty,’ not ‘witch hunt’ Will McConnell and Ryan put party over country in defense of Trump? Overnight Cybersecurity: Questions mount over N. Korea's ties to ransomware attack | House passes cyber crime bill | NSA leakers plan to release more hacking tools MORE, running for Senate in Maine, faces a common attack in the new Crossroads ad, which calls him "King Angus" — a title the U.S. Chamber of Commerce has used in its attacks as well. The ad says that "King Angus" "seems to have let down his subjects, the people of Maine" by supporting cuts to school funding and by turning the state's budget surplus into a deficit during his time as governor.

Both the National Republican Senatorial Committee and the Democratic Senatorial Campaign Committee have invested in the Maine race in recent weeks, as Republicans believe they see an opening for their candidate, Charlie Summers, to eke out a win.

Though King retains a lead in most recent polls, Summers was able to close that lead down to single digits in a mid-September poll, and Republican attacks seem to be doing enough damage to spark the Democrats into joining the fight. Though King is independent, he's expected to caucus with Democrats — likely the reason why the DSCC hasn't endorsed the Democratic nominee in Maine, Cynthia Dill, who is unlikely to pull out a win in November.

The spots airing against Rep. Joe DonnellyJoe DonnellyUpdated fuel regulations would modernize options at gas pumps Mnuchin mum as Dems press for answers on tax reform, Dodd-Frank Overnight Defense: Senate passes funding bill | Trump to get Afghan war plan next week | Concerns grow over Army nominee MORE in Indiana, Heidi HeitkampHeidi HeitkampSeparating fact from fiction in the Regulatory Accountability Act Heitkamp, Manchin under pressure over GOP regs bill Overnight Energy: Senate panel advances regulatory reform bills MORE in North Dakota and Sen. Jon TesterJon TesterSenators introduce lifetime lobbying ban for lawmakers A lifeboat for flood insurance: Roll back out-of-date government ‘safety net’ McConnell promises women can take part in healthcare meetings MORE in Montana all tie the Democratic candidates to Obama's policies, charging that their support of the policies is equivalent to support for for tax hikes and more spending.

The ad against Donnelly features a photo of him leaving Air Force One with the president, while the North Dakota ad calls Heitkamp a "rubber stamp" for Obama because of her support for the government bailout of the financial system. And the ad running against Tester gets specific, charging that Obama's budget includes "massive defense cuts" that would cut jobs from Malmstrom Air Force Base in Montana and that Tester voted to cut funds from farm programs, "hurting Montana farmers and ranchers."

Crossroads's ad running against Democrat Tim KaineTim KaineSinclair deal puts heat on FCC Senate Dem: Comey firing an 'attempt to obstruct' Russia investigation Trump bombshell: FBI’s Comey fired MORE in Virgina calls him "tax-loving," riffing off the state's motto that "Virginia is for Lovers." It charges that Kaine would raise taxes on "those who can least afford it" and notes his support for Obama's healthcare reform law, which the ad says will raise taxes on the middle class.

And Rep. Shelly Berkley in Nevada is targeted for potential ethics violations, for which she's currently under investigation by the House Ethics Committee. The ad running against her features clips from news reports highlighting aspects of the investigations, and notes that she's been named one of Washington's most corrupt lawmakers by a nonpartisan government watchdog group.

Crossroads GPS is launching another ad against Sen. Sherrod BrownSherrod BrownOvernight Finance: Trump moves to begin NAFTA talks | Dems press Treasury chief on taxes, Dodd-Frank | Biz leaders want tax changes to be permanent Mnuchin mum as Dems press for answers on tax reform, Dodd-Frank Sherrod Brown looks to defy Trump trend in Ohio MORE in Ohio, which will be released later this week.

Democratic Senatorial Campaign Committee spokesman Shripal Shah dismissed the ads as an effort to "prop up" candidates that would be "loyal rubber stamps for Rove's special interest agenda."

"Rove knows that these Tea Party Republicans will do as he says and put private insurance companies, Big Oil, and millionaires ahead of seniors, small businesses and the middle-class so he’s spending unprecedented amounts of cash supporting their campaigns.  Rove’s dangerous, anti-middle class agenda is wrong for our country and these desperate attack ads are solely designed to distract voters from the consequences of these policies," he said in an email.

--This post was published at 3:54 p.m. and updated at 5:25 p.m.