Now that the Republicans have determined that any fool can write a letter to foreign governments, I think it is our civic responsibility to respond in kind:
To the Government and People of Iran:
Recently 47 US Senators wrote your government with the clear purpose of undermining discussions to improve relations between Iran and the International Community. These 47 Senators have no right to speak for the American people or their elected government, let alone the rest of the world. The US clearly elected President Obama in 2008 and 2012 and, as our elected Executive, he alone has the right to speak on behalf of the American people.
Since these Senators seek to undermine any effort at peace I think it is appropriate that you and your government call out each and every one of these US Senators as what they truly are: turds. Knowing that Republicans are completely in bed with the oil and corn lobbies... well, use your imagination. If only our Democracy was capable of flushing this refuse. Someday.
I write on behalf of the American people... since that appears to be the precedent now.