Joe Biden on Sunday dropped out of the US presidential election and endorsed Vice President Kamala Harris as the Democratic Party’s new nominee, in a stunning move that upends the 2024 race for the White House. The 81-year-old Biden stepped aside after weeks of pressure from Democrats following a disastrous debate performance, throwing the election battle against Republican Donald Trump into unprecedented turmoil. “While it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and focus solely on fulfilling my duties as …