Independent fact-checkers declared Rep. Martha McSally’s new ad attacking her opponent’s patriotism to be false.

PolitiFact Arizona rated McSally’s attack ad “mostly false” on Monday, saying McSally’s ad “ignores critical facts that would give a different impression.”

McSally, a two-term Republican running for the Senate seat being vacated by Sen. Jeff Flake, used the ad to contrast her military record with her opponent, Rep. Kyrsten Sinema, a Democrat, who protested the Iraq War.

The ad includes side-by-side photos taken around the same time–one of McSally in her Air Force uniform and another of Sinema protesting the war in a pink tutu in 2003.

In the ad, which was released on Aug. 23, McSally said, “While we were in harm’s way in uniform, Kyrsten Sinema was protesting us in a pink tutu and denigrating our service.”

According to source documents reviewed by PolitiFact, Sinema was an organizer of student protests against the Iraq War while a law student at Arizona State University. But, PolitiFact notes, while Sinema protested the war and the Bush administration, there is no evidence she denigrated American troops’ service, as McSally claimed in the ad.

McSally has frequently seized on Sinema’s past activism in an attempt to draw contrasts between them and has dismissed criticism that the ad was a “cheap shot.”