In the latest Congressional attempt to sabotage peace talks, 47 Republican senators have taken the unusual step of directly threatening Iranian leaders that, if a deal were reached, it would not survive after Barack Obama leaves the presidency.

In an open letter (pdf) sent Monday to the "Leaders of the Islamic Republic of Iran," the entire leadership of the Senate Republicans warned, "We will consider any agreement regarding your nuclear-weapons program that is not approved by the Congress as nothing more than an executive agreement between President Obama and Ayatollah Khamenei."

"The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of an agreement at any time," continues the letter, which was organized by Senator Tom Cotton (R-Ark.)—who has vigorously opposed a deal with Iran. In 2013, he went so far as to propose legislation that would punish family members of people who violate U.S. sanctions against Iran.

Signatories to the letter include potential candidates for the 2016 presidential elections: Sen. Marco Rubio (Fla.), Sen. Rand Paul (Ky.), Sen. Ted Cruz (Texas) and Sen. Lindsey Graham (S.C.).

First reported by Josh Rogin for Bloomberg, the letter was presented as a lesson on U.S. politics for Iranian heads of state who "may not fully understand our constitutional system."

However, the veiled threat did not go unnoticed by major media outlets, which carried headlines like, "Republicans warn Iran against nuclear deal with Obama."

Jamal Abdi of the National Iranian American Council told Common Dreams that the letter was "a very desperate move" that "plays into the arguments of Iranian hardliners who oppose negotiations." Abdi added, "It is telling that hardliners in Washington are directly reaching out to their counterparts in Iran to try to kill a deal."

The letter was released less than a week after Israeli Prime Minister Benjamin Netanyahu delivered a controversial Congressional, which was boycotted by nearly 60 lawmakers, urging against a nuclear deal with Iran.

According to Abdi, "This is interference at the worst time, when the U.S. and Iran are negotiating over the final elements of a deal, particularly sanctions relief."

While the letter was signed solely by members of the Republican Party, attempts to sabotage Iran talks have spanned both sides of the political aisle. Analysts have repeatedly warned that stakes are high, as a disintegration of diplomatic discussions would likely lead to military escalation, and potentially war.