By now, we all know how thin-skinned our GOP nominee is, and how he lashes out anytime he feels he’s been insulted. In fact, we’ve never had a more paranoid, or sensitive candidate.

It’s a new day, so it’s time for a new target. This time, it’s former Defense Secretary Robert Gates.

Gates wrote an op-ed for the Wall Street Journal on Friday, where he described both candidates, Trump and Clinton, as unprepared to lead on national security.

Gates, who ran the Pentagon under Presidents George W. Bush and Barack Obama, is critical of Democratic nominee Hillary Clinton, citing her advocacy for the invasion of Libya, her reversal on trade agreements she supported as secretary of state, and her opposition to the troop surge in Iraq.

“She has much-discussed credibility issues apart from national security, but these also influence foreign perceptions of reliability and trust,” Gates writes.

In other words, she’s incompetent and untrustworthy.

But he savages the Republican nominee over several paragraphs, saying Trump is “in a league of his own” when it comes to demonstrating his credibility on foreign affairs. Gates rips Trump for his famous wall, his vocal support of torture, his embrace of Russian strongman Vladimir Putin, and his skepticism of NATO. He also attacks Trump as “cavalier about the use of nuclear weapons,” with “a record of insults to servicemen, their families and the military.” He criticizes the GOP standard-bearer as “willfully ignorant about the rest of the world, about our military and its capabilities, and about government itself.”

“He has no clue about the difference between negotiating a business deal and negotiating with sovereign nations,” Gates writes. “A thin-skinned, temperamental, shoot-from-the-hip and lip, uninformed commander-in-chief is too great a risk for America.”

I have no problem with that. In fact, it sounds like about as perfect of a description of the problem with Trump as any.

So, with that out there, and the fact that Trump has no ability to rise above criticism by offering reasoned and intelligent evidence to the contrary, he just rolls with it.

“We had a clown today, an absolute clown, Robert Gates,” Trump said at his rally in Colorado Springs. “He says bad about everybody that he’s worked for … He spoke badly about Bush, he spoke badly about Obama, he speaks badly about everything.”

“He’s a mess, okay, he’s a mess,” Trump said of Gates. “Look what he gave us, look at the mess of all these people that have been there for so many years. Look what we have, look at the Middle East.

“We’re in worse shape than we were 15 years ago by a factor of 10,” Trump said. “Much more importantly, the lives that we lost, because we’re dealing with incompetent people, we’re dealing with stupid people. We’re dealing with people like Robert Gates that don’t have a clue and then when they leave office, they criticize everybody.

“I don’t like critics, I like people that get it done and get it done right,” Trump said.

I won’t even point out the irony of Donald Trump citing incompetent and stupid people in control as the reason our nation is in a bind.

He went on to say about Gates that he”probably has a problem we don’t know about.”

Again. SO. MUCH. IRONY.

I doubt his shots at Gates bothered Gates to the same level of frothing breakdown. That’s the difference between those with emotional maturity and an aged man-child.