Why Brexit's back in the news: Britain and the EU struck a Northern Ireland trade deal

British Prime Minister Rishi Sunak (left) and European Commission President Ursula von der Leyen shake hands after a news conference at Windsor Guildhall, Windsor, England, Monday. The U.K. and the European Union ended years of wrangling, sealing a deal to resolve a dispute over Northern Ireland. (Dan Kitwood/AP)

LONDON — The United Kingdom and the European Union have signed a new agreement intended to solve one of the thorniest challenges created by Brexit: a long-term resolution for the trading status of Northern Ireland.

British Prime Minister Rishi Sunak reached a deal with European Commission President Ursula von der Leyen on Monday that will allow goods to enter Northern Ireland freely from other parts of the U.K.