A dark money group is boosting Sen. Claire McCaskill (D., Mo.) with a six-figure ad campaign less than a week after the politician decried the influence of dark money at a town hall.

After McCaskill called the 2010 Citizens United decision "the worst Supreme Court decision in our lifetime," the Chuck Schumer-linked 501 (c)(4) group Majority Forward announced Wednesday it had spent $500,000 in pro-McCaskill radio ads, the Kansas City Star reports.

The ads, which will air over a four-week period, tout the former Jackson County prosecutor's rural roots and her efforts to pass legislation meant to benefit rural hospitals. "A daughter of rural Missouri, Claire McCaskill's determined to protect rural health care. Born in Rolla, raised in the small towns of Houston and Lebanon, Mo., her father worked at the local feed mill. Her mother's family ran the corner drug store," the ad's narrator states.

The Missouri Democrat told a town hall last week that dark money groups on both sides of the aisle may spend up to $100 million leading up to the 2018 election, and she implored supporters to ignore any messages, for or against her, that were not from the official campaigns.

A spokesman for McCaskill told the Star that she stands by the remarks, while Majority Forward had no comment on her criticism of dark money campaigns.

McCaskill is considered vulnerable to being ousted by a strong Republican challenger, as she is running for reelection in 2018 in a state President Trump won handily in November.