In an unexpected foreign policy victory last week, the United States and five other world powers signed an unprecedented six-month agreement with Iran over the country’s controversial nuclear program. The new détente is a vindication of President Obama and Secretary of State John Kerry’s dogged diplomacy and of the newfound moderation of Iran under President Hassan Rouhani.

In exchange for $7 billion in sanctions relief, most of which would come in the form of oil revenue frozen in foreign banks, the Iranians agreed to disable their stockpile of uranium enriched to the 20 percent level, suspend future centrifuge installation and construction of its heavy-water reactor at Arak, and allow inspections of nuclear facilities, which have already begun.

Yet the usual chorus of naysayers is raising a clamor. Israel remains the accord’s most virulent opponent, with Prime Minister Benjamin Netanyahu denouncing the agreement as a “historic mistake.” Saudi Arabia’s disenchantment with the U.S., though not as overt as Israel’s, is increasingly palpable. In the U.S., neoconservative senators like Marco Rubio and Ted Cruz have staked out staunch opposition to the deal for not being hard enough on Iran.

It seems that nothing short of Iran’s unconditional surrender would satiate the critics. Already, a bipartisan group of senators is drafting additional sanctions for the U.S. to levy against Iran just as the fragile six-month accord begins. The senators seem to forget that sanctions are not designed to be permanent. They worked as intended here: Iran will back away from enriching its uranium stockpiles and only use uranium enriched below the 5 percent level—sufficient for energy production but nowhere near weapons-capability. The International Institute for Strategic Studies, a London think tank that closely studies the Iranian nuclear program, believes that the deal will effectively double the “dash time” it would take Iran to develop all the materials needed for nuclear weapons.

But instead of seeing the considerable developments, Senator Cruz wrote that Iran’s nuclear program must be scaled back by “ceasing the enrichment of uranium” entirely and “exporting any remaining stockpiles of enriched uranium.” Prohibiting a country from safely pursuing a nuclear energy program simply because the U.S. disagrees with its politics is fundamentally unfair. Furthermore, it is unthinkable that Iran would assent to such a humiliation voluntarily. As the only country to actually use nuclear weapons in war, it is telling that America pretends to possess moral superiority while chiding the world about the dangers of peaceful nuclear power.

Instead, the accord marks a hopeful source for reconciliation between the United States and Iran. More vituperative actions could not have seriously curbed Iran’s nuclear weapon ambitions indefinitely. Better that the existing program be peacefully extinguished through diplomatic means instead of attempting explosive actions that would further endanger American interests.

Much has yet to be determined when the negotiations with Iran resume in six months. But enough has been done to make us hopeful that success is possible.