"Carpet bombing would be completely useless. It's totally contrary to the American way of war," Gates said Tuesday on MSNBC's Morning Joe. "Total disregard for civilians. So, I mean, part of the concern that I have with the campaign, particularly when it comes to national security, is that the solutions being offered are so simplistic and so at odds with the reality of the rest of the world, with the way the world really works."
Texas Sen. Ted Cruz had previously vowed: "We will carpet bomb [the Islamic State] into oblivion. I don't know if sand can glow in the dark, but we're going to find out." The remarks were made at the Rising Tides Summit in Cedar Rapids, Iowa, last month.
Gates went on to make thinly veiled references to Trump and retired neurosurgeon Ben Carson, both political outsiders
"I will tell you this: I do think that politics is a profession," he said. "And I think that if you don't have any experience in how government works, if you have never been in government, your ability to make the government work is going to be significantly reduced."
He continued: "It's different than business. It's different than surgery. It's different than anything else. It's a skill set that you bring based on experience and based on dealing with other people."
Gates, a Republican, served as defense secretary under Presidents George W. Bush and Barack Obama. He also served as deputy director of the CIA under President Ronald Reagan, and later served as director. Gates wrote an op-ed for The Washington Post in December called "The kind of president we need."
"Recently, we have elected presidents with a conservative agenda or a liberal agenda," he wrote. "This election, how about we look for one whose agenda is just making things work?"