With Sen. Tom Cotton presiding over the Senate, the chamber’s Democratic leaders lambasted the open letter the Arkansas Republican spearheaded with 46 other Republicans to the leadership of Iran.

Minority Leader Harry Reid criticized Cotton’s effort, noting the Republican had only served in the Senate for roughly two months before leading the letter and saying his Democrats did not take similar action during President Gorge W. Bush’s administration.

“When it comes to preventing Iran from obtaining a nuclear bomb, we should put partisanship way to one side. Sadly though, the judgment of my Republican colleagues seems to be clouded by their abhorrence of President [Barack] Obama,” Reid said. “Let’s be very clear: Republicans are undermining our commander-in-chief while empowering the ayatollahs.”