"For 30 years, I served everywhere, from Iraq to Somalia, where I've been responsible for the lives of our sons and daughters," Eaton says. "For all of them, and for our country, I cannot support Donald Trump."
Eaton is best known for leading the training effort for Iraqi troops early in the Iraq War. He now serves as an adviser to the National Security Network, a liberal-leaning think tank.
"Donald Trump doesn't have the temperament of judgment to be our commander in chief," Eaton says.
The message echoes Clinton's criticism of her opponent as too reckless and ill-informed to make serious national-security decisions, but she is never mentioned in the new ad.
The spot will join several already airing in battleground states as part of a multimillion dollar ad campaign on Clinton's behalf. Most of the super PAC spending, which is separate from Clinton's own television and other advertising, focuses on attacking Trump. Clinton is spending most of her television ad money to air positive ads that portray Clinton as a lifelong advocate for children and families. She is also airing ads in battleground states such as Florida and Ohio.