On the second day of his visit to Poland, US President Joe Biden is due to deliver a speech in Warsaw on Saturday addressing the ongoing Russian invasion of Ukraine. The president’s appearance at Warsaw’s Royal Castle is scheduled for the late afternoon between 5 and 6 pm (1600 and 1700 GMT), according to the US embassy in the Polish capital. Beforehand, Biden is scheduled to meet with Polish President Andrzej Duda at the presidential palace. Also on the US president’s schedule is a visit Warsaw’s National Stadium with Polish Prime Minister Mateusz Morawiecki and Warsaw Mayor Rafal Trzaskowski…