Bloomberg | Bobby Ghosh: It was the smallest of gestures, and might easily have been missed if it wasn�t for the identities of those involved. In the chamber of the United Nations Security Council on Thursday, the American ambassador to the UN walked over to her Iranian counterpart to offer condolences.

Kelly Craft was responding to a speech by Majid Takht-Ravanchi, in which the Iranian ambassador mourned the death of Ava, a two-year-old girl in Tehran, whose doctors had been unable to procure bandages for skin blisters caused by a rare genetic disease. Takht-Ravanchi blamed U.S. sanctions � specifically, their impact on supplies of essential medicines.

It would�ve been easy enough to dismiss the story as a disingenuous play for sympathy, and an opportunistic attempt to deflect blame by a regime that has in recent weeks slaughtered hundreds of its own citizens�including children. But Craft was right to express compassion for the plight of ordinary Iranians. In fact, a bigger, more meaningful gesture is long overdue: making sure no other Ava need die for her government�s faults.

Medicines and foodstuffs are exempted from the U.S. sanctions on Iran, but the prospect of punishment has spooked potential suppliers, and especially foreign banks. Although this problem is easily fixed, President Donald Trump�s administration has been shamefully tardy in doing so.

What it will take is for the U.S. to green-light a proposed Swiss channel for humanitarian trade, and to expand the channel�s mandate to include non-Swiss suppliers. The channel has been in the works for more than a year. The most obvious European beneficiaries would be Swiss drugmakers Roche Holding AG and Novartis AG, and the food group Nestle SA, which have a long history of trade with Iran. But there�s no logical reason other companies, even American ones, shouldn�t be allowed to use the conduit.

U.S. authorities have blocked the channel, mainly by dragging their feet in clarifying what they would and would not allow through it. Some progress was announced in October, and still more earlier this month.

This isn�t good enough. While it�s true that the Iranian regime uses the sanctions as a convenient cover for its own failings � and some of the medical shortages are of its own making � there�s no gainsaying that trade restrictions inflict real pain on many people. Human-rights groups have documented how the sanctions harm Iranians� right to health.

At the same time, they have encouraged European governments to seek alternative routes such as INSTEX, a so-called �special purpose vehicle� designed to sidestep the American financial system. It hasn�t worked yet. But it has put the Trump administration in the unedifying position of threatening its allies over humanitarian trade.

American intransigence on this has also given Iran a stick with which to beat the Europeans. When not shedding crocodile tears over Ava, the regime in Tehran threatens to ratchet up its enrichment of uranium, unless Europe opens up trade channels.

By clearing the legal and bureaucratic path for the Swiss channel, the Trump administration would not only be doing the right thing by the Iranian people, it would be revealing the regime�s threats for what they are: nuclear blackmail. It would also free the Europeans to impose sanctions of their own, guilt-free.

All of this is long overdue. But if politics requires a propitious moment for the big gesture, it so happens that one is close at hand: January marks the 40th anniversary of Switzerland�s role as the de-facto representative of American interests in Tehran. It�s hard to think of a better time to announce a Swiss-American humanitarian channel.

And should the channel need a name, something more meaningful than �INSTEX,� something that conveys a political message as well as a humanitarian one ... how about Ava?