US President Joe Biden meets his fellow NATO leaders on Tuesday for a landmark 75th anniversary summit aimed at projecting strength and shoring up support for Ukraine in its defence against the Russian invasion. However, questions surrounding Biden’s mental fitness for office loom over the summit, as the US presidential race heats up between the president and his predecessor, longtime NATO critic Donald Trump. Founded in Washington in 1949 by the United States and 11 other countries at the onset of the Cold War to deter the expansion of the communist Soviet Union, NATO has grown to 32 members …