WASHINGTON (AP) — President Joe Biden heads to the United Kingdom to pay his respects to Queen Elizabeth II at a time of transition in US-UK relations, as both a new royal and a new prime minister are settling in. The rise of Prime Minister Liz Truss, who once called the US-UK relationship “special but not exclusive,” could mark a decidedly new chapter in the trans-Atlantic partnership on trade and more. Of high concern for Biden officials in the early going of Truss’s premiership is her backing of legislation that would shred parts of the post-Brexit trading arrangements in Northern Ireland.