Tom Cotton (R-AR) in Little Rock in November. (Justin Sullivan/Getty Images)

Sen. Tom Cotton (R-Ark.) got into a Twitter fight with the foreign minister of Iran.

Minister Javad Zarif said Wednesday at an event at New York University that sanctions against Iran could be lifted against Iran if an agreement was signed and the Security Council approved it, "whether Sen. Cotton likes it or not," according to the New Yorker.

The personal mention was no coincidence. Cotton has been one of the more vocal members of Congress on Iran, penning an open letter to the leaders of Iran on why a deal with the U.S. wouldn't be valid when President Obama left office if Congress and if a future president changed his or her mind. So obviously, he wasn't about to let that sort of comment go without firing back.

So Cotton responded on Twitter, challenging Zarif to a debate on the U.S. Constitution in Washington and going after him in pretty personal terms.

In Cotton's open letter to Iran's leaders, he wrote that they "may not fully understand [the U.S.'s] constitutional system," so he's probably pretty confident he'd win.

Zarif responded Thursday, characterizing Cotton's tweets as a "macho personal smear" and not "serious diplomacy." Oh, and he congratulated him on his new son.

International diplomacy has long involved a level of "macho" posturing, but thanks to social media, that macho posturing can take place for all to see. And retweet.