Biden vows a new era of ‘relentless diplomacy’ as the world contends with Covid, climate change and China

President Joe Biden defended his decision to end America’s longest war in Afghanistan in his address to the United Nations on Tuesday, a move that he says will allow the U.S. to pivot to other global challenges like the Covid pandemic, climate change and an ambitious China.

Biden’s debut address to the 193-member body since taking office in January comes as the U.S. president strives to rebuild alliances that crumbled under the reign of his predecessor and reclaim a global leadership position. He addressed a scaled-down gathering at the 76th United Nations...