Isn't the President Supposed to Conduct Foreign Policy?

I'm sure you've heard about this little effort by a group of Republican senators (well, a majority of Republican senators) to hamstring negotiations with Iran:

Bloomberg News reports on an open letter signed by 47 Republicans warning Iran that whatever they negotiate with President Obama can be undone in two years by the next President, who they presume will side with them.

Organized by freshman Senator Tom Cotton and signed by the chamber's entire party leadership as well as potential 2016 presidential contenders Marco Rubio, Ted Cruz and Rand Paul, the letter is meant not just to discourage the Iranian regime from signing a deal but also to pressure the White House into giving Congress some authority over the process.

“It has come to our attention while observing your nuclear negotiations with our government that you may not fully understand our constitutional system … Anything not approved by Congress is a mere executive agreement,” the senators wrote. “The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of the agreement at any time.”

(Emphasis added.)

It seems that Iran's foreign minister knows a bit more about it than our Republican senators do:

Zarif expressed astonishment that some members of US Congress find it appropriate to write to leaders of another country against their own President and administration. He pointed out that from reading the open letter, it seems that the authors not only do not understand international law, but are not fully cognizant of the nuances of their own Constitution when it comes to presidential powers in the conduct of foreign policy.

Foreign Minister Zarif added that "I should bring one important point to the attention of the authors and that is, the world is not the United States, and the conduct of inter-state relations is governed by international law, and not by US domestic law. The authors may not fully understand that in international law, governments represent the entirety of their respective states, are responsible for the conduct of foreign affairs, are required to fulfil the obligations they undertake with other states and may not invoke their internal law as justification for failure to perform their international obligations.

The Iranian Foreign Minister added that "change of administration does not in any way relieve the next administration from international obligations undertaken by its predecessor in a possible agreement about Irans peaceful nuclear program." He continued "I wish to enlighten the authors that if the next administration revokes any agreement with the stroke of a pen, as they boast, it will have simply committed a blatant violation of international law.

The president had a pointed response:

So did Vice President Biden, who was rather more thorough.

The author of this letter has been explicit that he is seeking to take any action that will end President Obama’s diplomatic negotiations with Iran. But to what end? If talks collapse because of Congressional intervention, the United States will be blamed, leaving us with the worst of all worlds. Iran’s nuclear program, currently frozen, would race forward again. We would lack the international unity necessary just to enforce existing sanctions, let alone put in place new ones. Without diplomacy or increased pressure, the need to resort to military force becomes much more likely—at a time when our forces are already engaged in the fight against ISIL.

[...]

This letter, in the guise of a constitutional lesson, ignores two centuries of precedent and threatens to undermine the ability of any future American President, whether Democrat or Republican, to negotiate with other nations on behalf of the United States. Honorable people can disagree over policy. But this is no way to make America safer or stronger.

[...]

In thirty-six years in the United States Senate, I cannot recall another instance in which Senators wrote directly to advise another country—much less a longtime foreign adversary— that the President does not have the constitutional authority to reach a meaningful understanding with them. This letter sends a highly misleading signal to friend and foe alike that that our Commander-in-Chief cannot deliver on America’s commitments—a message that is as false as it is dangerous.

The decision to undercut our President and circumvent our constitutional system offends me as a matter of principle. As a matter of policy, the letter and its authors have also offered no viable alternative to the diplomatic resolution with Iran that their letter seeks to undermine.

One thing, I think, that Biden's response and those of other Democrats miss: the Republicans want a war. That's their first response to anything: "Bomb, bomb, bomb -- Bomb, bomb Iran." The fact that they're so bad at it doesn't faze them in the least.

Even the Daily News doesn't think much of the Republicans' effort: