When Julian Assange published a huge cache of leaked files in 2010 that provoked global uproar over US tactics in foreign conflicts, he could hardly have foreseen the long legal battle ahead would culminate on a remote ocean archipelago.The Northern Mariana Islands is a string of tiny dots in the Pacific Ocean that until this week was known for its secluded beaches and wartime shipwrecks.But it found itself on Wednesday briefly at the centre of a geopolitical chessboard whose pieces have been manoeuvring in the shadows for years from Washington DC to London and beyond. Assange pleaded…