President Joe Biden is scheduled to give a speech in Warsaw on Saturday, with the White House saying the president will issue a call for Western unity and determination in the face of Russia’s military campaign in Ukraine. Biden is now in Poland, where at the time of reporting he was in a meeting with Polish President Andrzej Duda. Later in the day, Biden will meet with other Polish officials and Ukrainian refugees in Warsaw, to get a first-hand look at U.S. humanitarian efforts in the face of a massive wave of refugees fleeing the war. U.S. national security adviser Jake Sullivan told reporters at a White House press briefing on Friday that Biden plans to give a major address on Saturday in Warsaw, where he’ll “speak to the stakes of the moment” and the urgency of the challenges that lie ahead for the Western alliance as it responds to …