Nonetheless, no one in the international community has yet had the guts to confront Iran’s aggression in the region — including in Iraq and Syria — and its suppression of domestic dissent, including mass murders to enforce its anti-democratic idea of theological purity. We silently acquiesce to these threats and affronts in order to chase a nuclear deal that has eluded us year after year, and which the world wants far more than Tehran does.

Notwithstanding the stacks of evidence of Iran’s role in global and domestic terrorism — including the U.S. State Department’s own designation of Iran as the world’s number one state sponsor of terrorism and Amnesty International’s detailed reporting on shocking levels and methods of executions — the Iranian opposition gives us an insider’s look at the extent of Iran’s brutality. In fact, the National Council of Resistance of Iran offers a political as well as a cultural alternative to Islamic fundamentalism. It is led by a charismatic Muslim woman, Maryam Rajavi, and enjoys broad-based support among Iranians as well as Western politicians and policymakers.

Members of the NCRI and its main constituent organization, the Mujahedin-e Khalq (MEK) have been harassed, hunted and murdered by the scores inside and outside Iran’s borders. Approximately 3,000 members of the MEK currently live in squalor at Camp Liberty near Baghdad, confined there by Iraqi forces that are increasingly under the control of the Iranian Revolutionary Guards’ Quds Force. Many of those Iranian exiles barely had time to bury loved ones killed by those same forces in Camp Ashraf, Iraq, before the forced closure of that settlement and the move across the desert.

We would be hard-pressed to find a single NCRI member who hasn’t lost family to the mullahs’ reign of terror. Political dissidents were executed by the thousands across Iran near the end of the Iran-Iraq war in the 1980s. To this day, those accused of associating with the MEK or other opposition groups risk torture and execution — tactics also used against journalists, students, and human rights activists.

 One wonders why the Obama administration feels that this is a partner worth negotiating with. The betrayal of American values cannot serve American foreign policy interests. Negotiations over Iran’s nuclear program have failed to result in any material benefit to the international community. On the contrary. Iran’s supreme leader and foreign minister have both reiterated that they expect negotiations to result in the immediate removal of all economic sanctions against Iran.

Meanwhile, the latest proposal placed on the table by the Obama administration reportedly will let Iran keep many of its 10,000 operational centrifuges, thus doing little to limit Iran’s potential to develop a nuclear weapon. Our Congress must take all necessary measures to prevent such concessions.

 The unacceptability of a nuclear-armed Iran was the main premise behind the negotiations in the first place. But even if the talks were to succeed in keeping Iran from getting the bomb — and that success seems unlikely — the economic relief that Iran has already received in the past year will make the regime more dangerous. The cash will help Tehran escalate its support for Hezbollah, Hamas and Islamic Jihad, and bankroll its intrusions into sectarian conflicts in Yemen and Bahrain.

These actions may not affect Americans directly. But we must realize that the regime’s architecture of violence and repression reaches beyond its own citizenry. The potential loss of our Yemeni base of operations in fighting al-Qaida in the Arabian Peninsula ought to convince us that Iran’s threat to our regional interests does not end with a nuclear weapons program.

 It will take guts to re-impose the economic pressures that brought Iran to the nuclear negotiating table. It will take guts to support the democratic alternative that the NCRI represents. But a clear understanding of the nature of Tehran’s threat should help us summon the courage to say enough is enough, and to make it clear that we will no longer back down at the negotiating table or in any place the mullahs seek to extend their reach.

 Patrick J. Kennedy, a Democrat, represented Rhode Island’s 1st Congressional District from 1995 to 2011.