South Carolina Sen. Lindsey Graham told NBC News Wednesday that GOP rival Donald Trump is “a guy melting down,” saying that Trump’s attention-grabbing move to read Graham’s personal cell phone number aloud to a crowd “just shows you what he’s like.”

“Would you want to give him the nuclear codes?” Graham said of Trump, laughing. “If he had a bad day, maybe he’d put ‘em on the internet!”

Asked if Donald Trump is thin-skinned, the 2016 hopeful replied, “I think what you’re seeing is a guy melting down. That it’s one thing to have a reality TV show but if you turn the presidential campaign into a reality show, you’ll eventually lose because Republicans want to win.”

“Hillary [Clinton] could walk all over him because he is so bombastic, so ill prepared to be commander in chief,” he added.

Trump and Graham have been warring since the real estate mogul entered the race last month, though their barbs escalated over the weekend when Trump questioned the military service of Graham’s close friend, Sen. John McCain of Arizona.

“How could anybody wanting to be commander in chief even suggest that John McCain and people like him are less than heroes?” Graham told NBC News. “He’s a train wreck, he’s a car wreck and I think he’s shown yet again why he’s not going to make it through this process.”

Appearing in Graham’s home state Tuesday, Trump suggested that Graham had once called him to ask for help securing bookings on FOX News Channel. He then read Graham’s cell phone aloud to the crowd.

In response, Graham released a video on IJReview.com showing him destroying his famed old-fashioned flip phone with a blender, a golf club, lighter fluid, and various other instruments of wreckage.

He told NBC News that the cell phone debacle was “not the most pleasant thing that ever happened to me but by no means the worst thing.”

And he joked that he’ll finally be moving on to a more advanced means of communication.

“Donald Trump has been able to do something my staff could not do for years: get me a new phone,” he said.