At least one Greitens staffer is listed on the "Friends" section of Murphy's Facebook page, indicating the campaign had access to the postings.

"This election is about creating jobs and bringing fundamental change to Missouri, not random social media posts," Greitens campaign manager Austin Chambers said in a written response to the Post-Dispatch.

He continued: "Robert Murphy fought for the media's right to write dumb gotcha stories, and for his own free speech right to say things that aren't politically correct, even things others, including Eric, don't agree with."

Missouri Republicans have a recent example of how politically dangerous it can be to riff on the subject of rape.

In 2012, Todd Akin, Republican nominee for the U.S. Senate, doomed his own campaign and set off a furious national debate by making the medically invalid suggestion that, with “legitimate rape,” women's bodies tend to automatically prevent pregnancy. He made the comment by way of defending his opposition to abortion even in cases of rape.

In the new commercial, Murphy, wearing a “Combat Veteran, Vietnam” cap and VFW insignia, says into the camera: “Koster never served his country, only himself . . . It just makes me sick.”

Murphy's publicly accessible Facebook page includes numerous expressions of support for Republican presidential nominee Donald Trump, who avoided service in Vietnam with four college deferments and one medical deferment. Near the start of his campaign last year, Trump famously diminished the heroism of Sen. John McCain, R-Ariz., and other former prisoners of war by declaring: “I like people who weren’t captured.”

Get Government & Politics updates in your inbox! Stay up-to-date on the latest in local and national government and political topics with our newsletter. Sign up! * I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.