Would Trump cancel his Putin meeting over the Kerch Strait clash?
A look back at 27 November 2018, when the maritime incident off Crimea began to affect diplomacy ahead of the G20 summit.

Would a clash at sea derail a planned summit meeting? On 27 November 2018, that was the question hanging over the G20 gathering in Buenos Aires, after U.S. President Donald Trump said he might cancel his scheduled meeting with Russian President Vladimir Putin because of Russia's maritime clash with Ukraine.
The clash had taken place on 25 November 2018 in the Kerch Strait. As later described, the Russian Federal Security Service (FSB) coast guard fired upon and captured three Ukrainian Navy vessels that were trying to pass from the Black Sea into the Sea of Azov on their way to the port of Mariupol. It was the first time that Russian forces had openly engaged Ukrainian forces during the Russo-Ukrainian War.
Trump's remark, made as the summit was due to open that week, tied the planned bilateral talks directly to the incident. The meeting with Putin was on the schedule for the Buenos Aires event, and the possibility of its cancellation showed how quickly events in the Kerch Strait had reached the level of great-power diplomacy.
A separate ruling in Paris
Another development concerned money rather than ships. On 26 November 2018, an international tribunal in Paris ordered Russia to pay Oschadbank, the Ukrainian state savings bank, 1.3 billion dollars.
The two items were unrelated in subject, but together they marked the days around 27 November 2018 as a period in which Ukraine's disputes with Russia were being pressed at sea, in international diplomacy and in a Paris tribunal.