Sure, sending a letter isn't making a treaty. But sending that letter is an attempt to unmake a treaty before the president is done negotiating. The senate's role is to ratify a treaty the president has negotiated, not to send a letter to our enemy warning them about the president's power to negotiate a deal.
What happened to politics stops at the water's edge?
I'm sorry, all this hyperbolic and delusional outrage by the left not credible. The left's "waters edge" hasn't stopped left wing politics since the start of the Vietnam war, if not long before. And it is not the first time Congress has written to a foreign government, to go-around the President and influence policy. Perhaps some of you have forgotten the "Dear Commandante Letter"?
In 1984 the Senate Majority Leader Jim Wright (D) of Texas and Edward P. Boland of Massachusetts, chairman of the House Intelligence Committee, and 8 other senior Democrats in the foreign policy field wrote Ortega voicing regret that relations between Nicaragua and Washington so poor.
The writers stressed that they opposed more money for the rebels against the Sandinista Government. "In a veiled reference to the Reagan Administration, the letter says that if the Sandinistas do hold genuine elections, those who are ''supporting violence'' against the Nicaraguan leaders would have ''far greater difficulty winning support for their policies than they do today.''"
And they offered to discuss these issues with Ortega and the junta.
Mr. Solarz concedes that the letter to Mr. Ortega took a distinctly sympathetic tone. ... As for the charge that such a letter is unusual and inappropriate, Mr. Solarz said members of Congress write to heads of state all the time, usually to protest human rights violations.
Besides, he added, ''our rights to oppose foreign policy are protected by the Constitution and our responsibility as members of Congress.''
http://www.nytimes.com/1984/04/20/us/congress-letter-to-nicaragua-dear-comandante.html
Or perhaps you have forgotten that in 2007, House Speaker Nancy Pelosi (D-CA) traveled to Syria in an expression of dissent against the Bush administration’s approach to Syria and terrorism. In fact, she sat down with the thug and, understandably, the White House disagreed with her actions. “There is nothing funny about the impact her trip to Syria has had,” said then National Security Council spokesman Gordon Johndroe. “On the contrary, these visits have convinced the Assad regime that its actions in support of terrorists have no consequences.”
http://www.arabnews.com/?page=7§ion=0&article=94673&d=7&m=4&y=2007
Past the water's edge? More like the deepest part of the Atlantic Ocean.