Sen. Tom Cotton (R-Ark.) on Thursday slammed the White House for mocking his knowledge of the Iran nuclear deal, saying his criticism of a proposal to buy heavy water is no joke.

“This guy at the White House may think it’s a laughing matter to subsidize Iran’s nuclear program, but I don’t. I think it’s a very serious matter,” Cotton said on MSNBC’s “Morning Joe.”

Read full story at The Hill.