With friends like these, who needs enemies?

About a week after his public fallout with tech CEO Elon Musk, President Donald Trump and former Fox News host and right-wing firebrand Tucker Carlson are taking shots at each other.

Carlson started after Trump over the president's handling of the conflict between Iran and Israel, calling Trump "complicit in the act of war" in a newsletter. On Truth Social, Trump fired back at Carlson, giving the host a derisive nickname, as he has with many of his past political opponents. “Somebody please explain to kooky Tucker Carlson that IRAN CAN NEVER HAVE A NUCLEAR WEAPON,” he wrote. USA TODAY has reached out to representatives for Trump and Carlson for further comment.

How did we get here? Well, to paraphrase an expert on breakups named Taylor Swift, we have "seen this film before."

Friendship experts previously told USA TODAY that public fallouts like these are important to pay attention to, as they shed light on messy aspects of friendship breakups that play out in all our lives. Shasta Nelson, a social relationships expert and the author of "The Business of Friendship: Making the Most of Our Relationships Where We Spend Most of Our Time," previously told USA TODAY that, when friends fall out in an unhealthy manner, it's especially easy for what could have been a peaceful split to spiral into a toxic feud.