Ankara and Moscow have made impressive progress recently on some tricky diplomatic issues. Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan met May 3 in the Russian resort of Sochi to discuss energy, weapons, tariffs, sanctions and the complexities of the Syrian civil war — even agreeing to set up de-escalation zones there.

But they can't seem to find their way past the "tomato crisis." Clearly, the symbolic tomato — while important — isn't really the problem.

The countries' relations have been strained since Turkey shot down a Russian millitary jet in November 2015. Sanctions ensued, on both sides. Most recently, Turkey’s Ministry of Agriculture in March imposed a 130% tariff on Russian wheat and other grains, and sanctions on rice, peas and sunflower oil from Russia. In 2016, Turkey bought $720 million worth of sunflower oil, $76 million of corn and $490 million of wheat from Russia. 

It's interesting that Russian Agriculture Minister Alexander Tkachev reacted to the Turkish sanctions using the same language Putin used to describe the jet incident — the event that marked the start of the trade war: that Turkey had stabbed Russia in the back. The agriculture minister claimed Russian farmers would lose $1.3 billion to $1.5 billion annually. After the Sochi meeting, Turkey agreed to lift the sanctions.