I mean senators.

Led by Tom Cotton, a group of 47 Republican senators have sent a letter to the president of Iran.

Quoted from Huffington Post:

The letter, organised by Sen. Tom Cotton (R-Ark.), concerns the ongoing negotiations between the U.S., several of its partner nations and Iran aimed at curbing Iran's nuclear program. The letter claims to offer a basic lesson in how the U.S. Constitution works, and warns leaders in Tehran that any deal that results from the negotiations will not necessarily be binding, could be modified at any time by Congress and might be discarded entirely by the next president.The letter -- which actually features a number of errors regarding the Constitution -- has been widely seen as an attempt to sabotage the ongoing talks by eroding Iranian leaders' trust in the United States.
In case you missed it, here are a few links:

http://abcnews.go.com/Politics/iran-...ry?id=29564985
http://edition.cnn.com/2015/03/10/po...ter-logan-act/
http://www.washingtonpost.com/blogs/...e-iran-letter/
http://www.politifact.com/truth-o-me...rrect-about-c/

Isn't this treason?