Many people in Britain and across Europe will breathe a sigh of relief today if, as expected, the British Parliament ratifies a new trade agreement with the European Union. The 11th-hour deal will prevent the collapse of a trading relationship that accounts for 43% of Britain’s exports and hundreds of thousands of jobs in manufacturing and farming. It will allow tariff-free commerce to continue — albeit with new snags and delays — across the English Channel after Jan. 1, when Britain’s exit from the E.U. takes full effect.
Prime Minister Boris Johnson, who won election a…
