Rogin, who was live tweeting the Funniest Celebrity in Washington D.C. Contest, said he was struck by the comedian in the face.
Dan Nainan just punched me in the face. Not a joke.

Josh Rogin
@joshrogin
Dan Nainan just punched me in the face. Not a joke.
He was allegedly punched three times.
@JeffreyGoldberg @joshrogin he punched him 3 times

Michelle Fields
@MichelleFields
@JeffreyGoldberg @joshrogin he punched him 3 times
Police were called over the alleged assault.
We are calling the police on Dan Nainan who just punched me twice in front of several witnesses. #dcimprov

Josh Rogin
@joshrogin
We are calling the police on Dan Nainan who just punched me twice in front of several witnesses. #dcimprov
Before Rogin was punched, he wrote a critique of Nainan's jokes.
Dan Nainan was funny until he dusted off his 2005 Katrina jokes in a gratingly bad GWB impression. #DCImprov

Josh Rogin
@joshrogin
Dan Nainan was funny until he dusted off his 2005 Katrina jokes in a gratingly bad GWB impression. #DCImprov
Dan Nainan makes his umpteenth joke about how Asians cant distinguish between letters "L" and "R". Election, erection, we get it. #DCImprov

Josh Rogin
@joshrogin
Dan Nainan makes his umpteenth joke about how Asians cant distinguish between letters "L" and "R". Election, erection, we get it. #DCImprov
CNN's Candy Crowley was also at the competition.
And Ralph Nader, who Rogin said opened, "by saying he isn't funny and proceeds to live up to his word."
Police later arrived at the scene:
DC improv night:

Michelle Fields
@MichelleFields
DC improv night:

Nainan reportedly was arrested after the incident.
DC police arrested Dan Nainan for assaulting me.

Josh Rogin
@joshrogin
DC police arrested Dan Nainan for assaulting me.
Rogin said he was fine, and implied the attack was sparked by his tweets.
Thanks for all the support tweeps. Physically I am fine. Just not used to getting attacked for tweets.

Josh Rogin
@joshrogin
Thanks for all the support tweeps. Physically I am fine. Just not used to getting attacked for tweets.
Eli Lake, senior national security reporter for Daily Beast, tweeted he spoke with Rogin after the incident.
Just talked to @joshrogin. He was sucker punched by @comediandan who is an unfunny lunatic that we all had to google because he's a nobody.

Eli Lake
@EliLake
Just talked to @joshrogin. He was sucker punched by @comediandan who is an unfunny lunatic that we all had to google because he's a nobody.
Update — Sept. 25, 2013, 12:40 p.m. ET:
Rogin described the incident to The Washington Post:
"He said, 'Are you Josh Rogin?' I said yes, and he punched me in the jaw."
Nainan also pushed him, Rogin said, then briefly walked away – only to return to take two more swings. (One connected, Rogin said.)
Rogin said he was surprised by the attack. "I didn't think I was being too harsh with him – he's a professional comedian and I was being a professional journalist."
Also: "My face hurts."
