Ukraine (probably) attacked and damaged several Russian naval ships in port in Sebastopol. In response, Putin cancelled the deal allowing food exports from Ukraine.

Zelensky said that Putin had already unofficially blocked food exports and was only pretending that the deal still operated. That would make it legitimate to retaliate with a naval attack. But what the world really needs is a resumption of food exports.

Months ago, before this deal, I suggested that Ukraine could attack a Russian oil tanker returning empty to Novorossiysk to pick up a new cargo.

Then, after the food deal was agreed, I said that as long as the deal continued, Ukraine should refrain from any attacks on Russian shipping.

Now that the deal has been terminated, that conclusion no longer applies. Ukraine could put tremendous pressure on Putin by interdicting Russia's main channel for oil export. If Ukraine offers to allow oil commerce to proceed provided the food commerce can too, that would be a magnanimous offer.

Later Putin said Russia would resume the food export deal. Whether he will implement the deal honestly remains to be seen, but let's hope he does.