A 58,000-ton oil tanker called the Mikati was ploughing through the waters of the Indian Ocean one day when it got some bad news from faraway Brussels: it had been added to a list of sanctioned vessels in Russia’s shadow fleet. The story of the Mikati, currently passing through the English Channel, illustrates the strengths and weaknesses of the European Union sanctions regime that now includes some 600 ships. The EU listed the Mikati in July, following a similar decision by Britain in November last year. Built in 2003, its advanced age makes…