The top Republican candidate running to face Sen. Claire McCaskill Claire Conner McCaskillMomentum growing among Republicans for Supreme Court vote before Election Day Democratic-linked group runs ads in Kansas GOP Senate primary Trump mocked for low attendance at rally MORE (D-Mo.) in November's midterm elections attacked McCaskill over her support for former Democratic presidential candidate Hillary Clinton Hillary Diane Rodham ClintonBiden leads Trump by 36 points nationally among Latinos: poll Democratic super PAC to hit Trump in battleground states over coronavirus deaths Battle lines drawn on precedent in Supreme Court fight MORE in a new digital ad released Monday.

McCaskill, who is considered one of the most vulnerable Senate incumbents on the ballot this fall, was the first member of Congress to endorse Clinton's 2016 presidential bid. McCaskill became one of the former secretary of State's most vocal backers on the campaign trail.

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The new online spot, shared exclusively with The Hill ahead of its Monday release, is meant to hammer home McCaskill's ties to Clinton and amplify Clinton's attacks on Trump supporters.