The former Navy SEAL responsible for killing al-Qaeda leader Osama bin Laden offered some harsh advice for Democrat presidential candidate Pete Buttigieg, who often touts his five months in Afghanistan on the presidential campaign trail.

“My advice for Pete Buttigieg… Stop playing war hero. You’re gonna get called out,” wrote Robert O’Neill on Twitter.

My advice for @PeteButtigieg … Stop playing war hero. You’re gonna get called out. — Robert J. O'Neill (@mchooyah) February 12, 2020

Former South Bend, Indiana mayor Buttigieg, coming off two strong performances in the Iowa and New Hampshire primaries, often references serving as a naval intelligence officer as a primary qualification for his fitness to serve in the Oval Office.

“When I was deployed, I felt it. I felt that the flag on my shoulder was keeping me safe because it stood for a country that was known to our allies and our adversaries to be one that keeps its word,” Buttigieg told a crowd in Iowa last month. “And when I’m your commander-in-chief, no ally will ever have reason to question whether it’s a good idea to bet your life on the credibility the United States of America.”

As U.S. Marines Greg Kelly and Katie Horgan write in the Wall Street Journal, however, veterans often “roll their eyes” when Buttigieg talks of his time in the Navy. Kelly and Horgan note Buttigieg jumped on the fast-track to becoming a military officer through a direct commission in the reserves, circumventing the years of intense training and preparation that most must go through to achieve such a status.

“Mr. Buttigieg skipped all that—no obstacle courses, no weapons training, no evaluation of his ability or willingness to lead,” the Marines write. “Paperwork, a health exam and a background check were all it took to make him a naval officer.”

The two Marines also reference Buttigieg’s book chronicling his time as a war tourist with time to relax and read.

“Working eight-hour days,” Buttigieg wrote discussing his time stationed at a base in Illinois, featured “a relaxing contrast from my day job, and spending time with sailors from all walks of civilian life, was a healthy antidote to the all absorbing work I had in South Bend.”

When writing about his five months spent in Afghanistan, Kelly and Horgan point out, Buttigieg marveled at having “more time for reflection and reading than I was used to back home,” saying he would take “a laptop and a cigar up to the roof at midnight to pick up a Wi-Fi signal and patch via Skype into a staff meeting at home.” The Marines note: