When President Barack Obama began negotiations over the status of Iran’s nuclear program, he took a hard line. He insisted that Iran had no right to enrich uranium and said that if Iran wanted relief from international sanctions, it had to dismantle its enrichment infrastructure and had to comply with the International Atomic Energy Agency’s investigation into the possible military dimensions of its nuclear program.

When the preliminary terms of the deal were announced this spring, it emerged that Obama had abandoned all of those positions during the negotiations. We were told then, however, that Iran had agreed to “anytime, anywhere” inspections of its declared or suspected nuclear facilities.

Under the final agreement, announced this month, it emerged that international inspectors may have access to suspected nuclear sites, but only after the conclusion of a process of negotiation that will last a minimum of 24 days and which could be drawn out far longer than that. Worse still, in recent days senior Iranian officials have claimed that military sites are off limits to any inspection.

Moreover, the deal ends sanctions unrelated to Iran’s nuclear program — on its purchase of heavy conventional weapons (in five years from now), on its purchase of ballistic missile technology (in eight years from now), and (almost immediately) on Iranian officials and organizations sanctioned for their international terrorist activities.

Judged by the standards set by this administration, the Iran deal is an appalling capitulation. By any standard, it is a national humiliation: despite all our concessions, we could not secure in return even the freedom of four American citizens now held captive by the Islamic Republic.

It is just possible, however, that accepting the deal is America’s least-bad option. If President Obama could have negotiated a better deal, he would have; parties to the negotiations insist that increasing the sanctions on Iran would have driven the regime to accelerate its nuclear program; and war with Iran would be fraught with danger and uncertainty.

It is not at all obvious how our country should proceed at this moment. Whether to accept the Iran deal is most important foreign policy issue in more than a decade, and in a free country with a republican form of government, no one person — especially one who will never again answer to the voters — should have the exclusive right to dictate policy to 300 million people.

That is why our Constitution provides that the president has power to make treaties “by and with the Advice and Consent of the Senate, … provided that two-thirds of the Senators present concur.”

Alexander Hamilton justified this provision in Federalist 75 by observing that “it would be utterly unsafe and improper” to entrust the power to make treaties wholly to the president. No one at the time disagreed. Our ancestors had had enough of kingly power.

How times have changed.

Although our arms-control deals with the Soviet Union were negotiated as treaties, and subsequently either approved or rejected by the Senate, the Obama administration chose not to negotiate the deal with Iran as a treaty.

Instead, to avoid any meaningful congressional oversight, the deal was formulated as a resolution of the United Nations Security Council. After the deal was announced, leaders of both political parties asked the president not to approve a UN vote until after the Congress had a chance to study its terms and to weigh its merits.

Obama refused: the Security Council approved the deal on Monday. That means that the United States has already agreed to end the international sanctions against Iran. Nothing Congress does can change that reality.

Thus the upcoming debate in Congress, pursuant to the Iran Nuclear Agreement Review Act, is just a sideshow. That measure provides that the president may not waive U.S. sanctions against Iran until mid-September, unless the Congress votes to forbid him from doing so. In that case, the president will veto the measure and waive the sanctions — unless opponents of the deal can override his veto.

But even then, even if there are overwhelming, bipartisan majorities in both houses of Congress to “kill” the deal, the deal won’t die: Iran still will be free of the UN sanctions, the U.S. will be in violation of its commitment to the Security Council, and Iran will have the right under the terms of the agreement to repudiate all of its commitments to restrain its nuclear program.

Meanwhile, in the Islamic Republic of Iran, lawmakers have the right to approve or reject the agreement.

Joseph R. Reisert is associate professor of American constitutional law and chairman of the department of government at Colby College in Waterville.