Former Defense Secretary Bob Gates has gone on the record this week criticizing the national security dialogue in the 2016 race for the Republican presidential nomination, saying it would “embarrass a middle schooler.”

Gates said Monday during a Politico Playbook event in Washington that “people are out there making threats and promises that are totally unrealistic, totally unattainable,” according to The Guardian.

“The level of dialogue on national security issues would embarrass a middle schooler,” he was quoted as saying about the GOP candidates.

Gates expanded on those comments during a Tuesday interview with MSNBC’s Andrea Mitchell. He said he was referring to candidates’ plans for dealing with the Islamic State terror group, including “carpet bombing them and making the sand glow and other such things.”

Mitchell noted Sen. Ted Cruz (R-TX) had proposed carpet-bombing the group and that real estate mogul Donald Trump had suggested taking away oil and other assets from the extremists.

“My view is, either they really don’t understand how difficult this is or they’re being pretty cynical and opportunistic,” Gates said. “They’re putting forward simple solutions that are simply unattainable as opposed to suggesting to the American people that these are complex problems that are going to take time to solve.”