In January, congressional Democrats and Republicans who are united in their skepticism of – if not outright opposition to – the interim Iran nuclear deal will attempt to pass a new round of economic sanctions against the Iranian people. This move would very likely scuttle the current six-month agreement, end negotiations toward a comprehensive settlement, and put us back on the path to war.

Congressional hostility toward Iran is rooted in a black-and-white worldview that runs as follows: the United States and Israel are liberal democracies that defend individual rights and human dignity, whereas Iran is a despotic theocratic regime that sponsors terrorism and would do anything within its power to wipe Israel off the map.

The world is rarely black and white, and conflicts are usually not resolved until each side understands the other's point of view. With that in mind, it may be worth pondering some inconvenient truths that would cause a fair-minded Iranian to doubt congressional wisdom.

The assertion that US policies are driven by a concern for human rights is not consistent with the history of US-Iran relations. As the CIA now admits, it overthrew a democratically elected Iranian government in 1953 and restored Shah Mohammed Reza Pahlavi to power. For the next quarter century, until the 1979 Islamic revolution, the US government supported the autocratic Shah – whose regime also enjoyed close relations with Israel.

The Shah's secret police – Savak – became increasingly brutal, ultimately detaining without trial and torturing tens of thousands of Iranian citizens. By the 1970s, the regime's brutality had been well documented in the west. For example, a 1976 report by the Geneva-based International Commission of Jurists concluded:

There is abundant evidence showing the systematic use of impermissible methods of psychological and physical torture of political suspects during interrogation.

Yet successive US administrations supported the Shah until the very end and then shielded him from prosecution after his overthrow.

Not only did the United States impose and support a regime that tortured innocent Iranians, there is also evidence that the CIA assisted Savak. A 1980 report on CBS's 60 Minutes documented close ties between these two organizations. An understanding of this history is especially important because it adds perspective to the US embassy hostage-taking drama that stretched over the last 444 days of the Carter administration. Many in Iran believed that US embassy staff had aided and abetted Savak and were thus fair targets for retaliation. One need not condone the hostage-taking to understand that it was not merely an unprovoked, sadistic act.

US maltreatment of Iran continued after the Shah's overthrow. It is now well known that the Reagan administration helped Iraq with "intelligence and military support" after Saddam Hussein attacked Iran in 1980 and launched a brutal eight-year war. "[I]t was the express policy of Reagan to ensure an Iraqi victory in the war, whatever the cost," Shane Harris and Matthew M Aid wrote in Foreign Policy magazine last year. With the administration's knowledge, Iraq used chemical weapons against Iranian forces, killing thousands. Declassified government records show that the Reagan administration, represented by special envoy Donald Rumsfeld, helped Saddam's military produce and deploy these awful weapons of mass destruction, which included biological as well as chemical agents.

In 1988, while the war was in progress, a US warship, the USS Vincennes, shot down an Iranian civilian aircraft over the Persian Gulf, killing all 290 aboard, including 66 children. The captain of the ship said it was under assault by Iranian gunboats at the time and that the Airbus A300 was misidentified as an attacking F-14 Tomcat. Iran countered that flight 655 left Iran the same time every day. Witnesses with Italy's navy and on a nearby US warship said that at the time it was shot down, the airliner was climbing. In 1996 the United States settled an Iranian claim against it at the International Court of Justice for $131.8m. While it was appropriate for the US government to accept responsibility, it could not make up for the Iranian people's losses: more innocent lives were snuffed out by this attack than were killed in the Pan Am 103 bombing over Lockerbie, Scotland.

The hostility toward Iran continued in the new century. Despite Iran's efforts to cooperate with the United States after 9/11 (the Shiite regime opposed both the Sunni Taliban and al-Qaida in next-door Afghanistan to the east), President Bush in 2002 included Iran as a member of the "axis of evil" along with North Korea and Iraq. The following year, the United States overthrew Saddam Hussein and occupied Iraq – placing US forces on both Iran's western and eastern flanks. Finally, in 2011, Iranian forces captured a US surveillance drone that was flying well within its air space – about 140 miles from the Afghanistan border.

Far from being innocent, US policy toward Iran appears downright hostile when viewed from the other side. Rather than continuing to tell ourselves tales, it is time we embrace the truth about our relations with Iran, which even American and Israeli intelligence agencies say is not building a nuclear weapon. We have a historic chance to end the destructive cold war with Iran, which, like it or not, will remain a major power in the Middle East. It would be a tragedy if Congress were to sabotage this opportunity.