Though a preliminary agreement was reached between American and Iranian negotiators on April 2 in Switzerland, the issues surrounding the new nuclear deal are far from over. As the New York Times points out, the presidents of both nations must “[sell] the agreement at home to constituencies deeply suspicious of both the deal and the prospect of signing any accord with an avowed enemy.” While the deal certainly indicates progress, intense political and cultural friction remains between the two states. In the international arena, the United States must balance the tasks of furthering diplomatic relations with Iran as well as appeasing hardline leadership in concerned regional states like Israel and Saudi Arabia.

On a domestic level, the nuclear talks have outlined the growing politicization of foreign policy as partisan politics have continued to impede progress. The debate has problematically dominated the headlines, as the story that is told has too often been one of political war instead of productive debate. The deal became a case of domestic politics playing out in the context of a foreign policy issue and, on both sides of the issue, things got undeniably ugly.

These domestic political tensions were exemplified in the March 9 letter penned by the junior Senator from Arkansas, Tom Cotton. The letter, signed by 47 Republican senators and addressed to “the Leaders of the Islamic Republic of Iran,” was fuel on the fire of Israeli Prime Minister Benjamin Netanyahu’s March 3 speech. On the eve of his pending reelection, Mr. Netanyahu delivered a speech to Congress regarding the Iran talks, having been invited discretely by Speaker John Boehner. As a Vox.com article outlined on the day of the speech, some considered the invitation, and the speech itself, “a major breach, both of diplomatic protocol…and of political protocol for Congressional Republicans to freelance their own foreign policy independent of the White House.” Both Netanyahu’s speech and Cotton’s letter detract from the issue at hand: the talks themselves. Rather than debate the question of whether sanctions should be lifted, or exactly what kind of inspections ought to be mandated for the Iranian nuclear program, these partisan skirmishes debilitate the diplomatic process.

In fact, the point is underscored perfectly by the Iranians themselves. The situation remains complicated, for both the Iranians and the Americans, by the many political authorities in Iran, where the Ayatollah Ali Khamenei possesses ultimate spiritual and political power and has long espoused anti-American hate. The Ayatollah, however, has more or less aligned with President Rouhani, who campaigned on a promise of ending crippling western sanctions, and the negotiators acting on his behalf. “No one in Iran is against the resolution of the nuclear issue through negotiations,” said Mr. Khamenei as quoted in a New York Times article last month. “What the Iranian nation does not want to agree with is the impositions and bullying of the Americans.”

Granted, the Ayatollah’s words may belie a section of faction of Iranian leadership that has historically acted in less than good faith. For much of the previous two decades, Iranian leadership has been at times duplicitous regarding its nuclear program, and the difficulty in discerning their nuclear tensions has resulted in the sanction program and very debates over this month’s deal. Nonetheless, it seems negotiators have taken the Iranian position at face value, to a degree (as they were able to reach a deal) and as such, the Ayatollah’s words reflect both his efforts at progress in the talks and his desire for a united Iranian front. To bluntly contrast the actions of Senator Cotton for example, there is Khamenei’s strategist Hamid Reza Taraghi, who was quoted in the same Times article as saying, “We will have no letters or other nonsense that we are witnessing in the United States…Iran speaks with one voice.”

In a recent video for the New York Times, reporter David Sanger noted the difficult reality that three deals need to be reached: one between American and Iranian negotiators, one between Mr. Obama and Congress, and one between the Iranian diplomats and their hardline counterparts in both military and religious circles. Although a deal was finally achieved, the politicization of the process in America has not been swept under the rug, lest it threaten the deal’s resolution in the months to its June 30 deadline, or the next issue at hand.

Certainly, the letter exemplifies a climate in which the Democrats and Republicans have had trouble reaching across the aisle to work together. It demonstrates the danger of domestic strife spilling publicly into the international arena. Iranian Foreign Minister Javad Zarif, blasted Senator Cotton’s letter on a number of points. “In our view,” he said, “this letter has no legal value and is mostly a propaganda ploy.” He expressed alarm at the letter’s violation of diplomatic principles, saying, “some political pressure groups are so afraid even of the prospect of an agreement that they resort to unconventional methods, unprecedented in diplomatic history.” Although Zarif’s responses may be taken with a grain of salt, given that he stood to gain in the negotiations from criticizing Senator Cotton’s play, his remarks provide a detailed criticism of this brand of American political disunion.

The Republicans’ letter makes two assertions that have especially been called into question both by domestic commentators and Mr. Zarif. Mr. Cotton argues that Congress will view “any agreement regarding [the Iranian] nuclear-weapons program that is not approved by the Congress as nothing more than an executive agreement,” between Mr. Obama and Mr. Khamenei. Pundits have been quick to point out that the required consensus of the P5+1 Joint Comprehensive Plan of Action was indeed reached by a coalition of five states and Iran. Vice President Joe Biden called the letter “beneath the dignity of an institution I revere,” referring to the Senate. Mr. Biden went on to challenge Cotton’s assertion that “the president does not have the constitutional authority to reach a meaningful understanding with [the Iranians],” a statement referring to the letter’s claim that Mr. Obama’s successor “could revoke such an executive agreement with the stroke of a pen.” Mr. Zarif rebutted this claim as well, reflecting the insulting nature of a letter purportedly aiming to teach Iranian officials, many of who were educated in the United States, about the constitution. Mr. Zarif noted, “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.” Parsing the pointed language of the Iranian Foreign Minister, there remains a strong argument for the notion that the letter did more harm than good to the good faith diplomatic progress in reaching a deal.

It may also be noted that the letter continues a tradition, amongst a faction of conservatives, of attempts to undermine executive power under the Obama Administration. Certainly, a hallmark of the American process is the system of checks and balances but at times, attempts to regulate the President’s power have fallen outside the realm of appropriate political behavior. In this vein, Senator Cotton’s letter recalls the ghosts of efforts to spur government shutdowns by Republican lawmakers and as far back as the questioning of Mr. Obama’s birth certificate around the time of the 2008 elections.

Regardless of lawmakers’ support—or lack thereof—for a deal with Iran, the agreement has been reached and a degree of progress achieved. As members of both parties reassess the conversations they had during the negotiations, the larger international issue of a nuclear deal seems to have outweighed domestic rivalries. While the Republicans may reel from what has been received as a victory for Mr. Obama, domestic sentiment remains concerned over the politicization of a foreign policy issue of this magnitude. When nuclear weapons and the fate of a region like the Middle East are involved to the degree they were in the Iran talks, political grandstanding has threatened vital diplomatic processes. In light of these events, American politicians seem to have forgotten the responsibility implicit in their election, to maintain respect for the constitutional powers of their peers and for the principles of diplomatic prudence.

Art by Eva Strauss.