Biden on Tuesday signed documents endorsing Finland and Sweden's accession to NATO, the most significant expansion of the military alliance since the 1990s as it responds to Russia's invasion of Ukraine. Biden signed the U.S. "instrument of ratification" welcoming the two countries, the final step for their endorsement by the United States... The U.S. Senate backed the expansion by an overwhelming 95-1 last week... NATO's 30 allies signed the accession protocol for Sweden and Finland last month, allowing them to join the nuclear-armed alliance once all member states ratify the decision. The accession must be ratified by the parliaments of...