Almost half the Senate — nearly every Republican — warned the Iranian government in a letter on Monday that if Obama makes an agreement with Tehran, it will not be legally binding.

The senators explained that the Constitution delegates to the Senate the power to approve the ratification of international treaties.  “Anything not approved by Congress is a mere executive agreement,” they wrote, and went on to explain that since the President will only be in office for a short period, unilateral agreements he makes could easily be reversed by the following president or Congress. In particular, any “nuclear-weapons program that is not approved by the Congress as nothing more than an executive agreement between President Obama and Ayatollah Khamenei.”

The letter, led by Sen. Tom Cotton (R.-Ark.), was addressed to Iran, but it also served as a warning to the Obama administration. The administration is headed for a framework agreement with Iran later this month that would gradually lift the sanctions on Iran in exchange for Iran agreeing to freeze its nuclear program.  The senators say the compromise has no teeth and doesn’t take into consideration Iran’s past failure to declare the existence of some of its nuclear facilities.

Predictably, Foreign Minister Javad Zarif dismissed the letter, saying it “has no legal value and is mostly a propaganda ploy.”

The media and Democrats reacted hysterically, calling the letter everything from a misstep to high treason. The senators were accused of trying to sabotage President Obama’s deal (the same one that Israeli Prime Minister Benjamin Netanyahu called a “bad deal”). Vice President Joe Biden strongly condemned the letter, saying it “offends me as a matter of principle” and is “beneath the dignity of an institution I revere.” Rep. Jared Polis (D-Colo.) called Cotton, who is a veteran, “Tehran Tom” on Twitter. The New York Daily News labeled the Republicans who signed the letter traitors, sparking a top trending #47Traitors hashtag on Twitter.

The comparisons to treason are rather ironic considering how many times Democratic members of Congress have conducted foreign business without the approval of — and against the wishes of — the President. Former Speaker of the House Nancy Pelosi visited Syria in 2007 to meet with President Bashar al-Assad, which President Bush labeled as “counterproductive.” Another former Democratic Speaker of the House, Jim Wright, participated in mediation talks between the ruling Sandinistas in Nicaragua and opposition contras, over President Ronald Reagan’s objections. Perhaps the ultimate hypocrisy is that Pelosi and Rep. Tom Lantos attempted in 2007 to take a trip to Iran. They were thwarted only because they were denied visas by Tehran.

Senator Cotton shot back, pointing out, “Joe Biden, as Barack Obama’s own [former] secretary of defense [Robert Gates] has said, has been wrong about nearly every major foreign policy and national security decision in the last 40 years.” He told ABC News, “We’re on the verge of a deal that could allow Iran to get a nuclear weapon in as little as ten years, so it’s important that Iran realize that Congress will not allow that outcome to happen.” Cotton warned during an appearance on Fox and Friends Monday morning that “Iran is a greater threat to the United States than the Islamic State of Iraq.”

Not to be outdone, Hillary Clinton declared, “The senators’ letter was out of step with the best traditions of American leadership.” (emphasis added)

Now who would fit into the “best traditions of American leadership” better than Thomas Jefferson? In his “Report of the Secretary of State to the President“, delivered in 1791, he said, “It is desirable, in many instances, to exchange mutual advantages by Legislative Acts rather than by treaty: because the former, though understood to be in consideration of each other, and therefore greatly respected, yet when they become too inconvenient, can be dropped at the will of either party: whereas stipulations by treaty are forever irrevocable but by joint consent. . . .”

In other words, when Jefferson was serving as our first secretary of state, he advised President Washington that even a legislative action treaty could easily be changed by either party, whereas a fully ratified treaty per Article II, Section 2 is irrevocable.

Article II, Section 2, Clause 2 of the U.S. Constitution empowers the President to propose and chiefly negotiate agreements between the U.S. and other countries. However, such agreements only become treaties after the advice and consent of a supermajority of the U.S. Senate.

This is exactly what the senators were stating: an Obama-only deal with Iran is not a legally binding treaty according to the U.S. Constitution. Jefferson recognized this fact — even applauded it — when he was himself (the irony, think Hillary) our first Secretary of State. If Hillary Clinton wants to argue that Jefferson is outside the best traditions of American leadership, she’s free to do so. But the rest of us should conclude that, with Jefferson, the 47 Senators are in pretty good company.