U.S. President Joe Biden delivers a speech on NATO at the Vilnius University in Vilnius, Lithuania, after the end of the NATO Summit, July 12, 2023.Andrew Caballero-Reynolds | AFP | Getty ImagesWASHINGTON — President Joe Biden galvanized NATO allies and reaffirmed U.S. commitment to Ukraine Wednesday as Russia’s devastating war on its neighbor marches past its 500th day.Biden, who faces reelection next year and has committed the lion’s share of military aid for Ukraine, described support for Kyiv’s fight for democracy as “the calling of our lifetime.”In the nearly 18 months since Russian troops poured over Ukrainian borders, marking the largest air, land and sea conflict since World War II, the U.S. has unleashed a war chest worth more than $41 billion to bolster Kyiv.”We did what we always do. The U.S. stepped up, NATO stepped up and our partners in the Indo-Pacific stepped up,” Biden said in an address from Vilnius, Lithuania.”We will not waver,” he said, promising that the U.S. will continue to support Ukraine “for as long as it takes.”Biden’s address follows a two-day high-level meeting of NATO leaders gathered in Lithuania’s capital, where member countries made security guarantees for Ukraine. The allies welcomed the arrival of Ukrainian President Volodymyr Zelenskyy, who reiterated calls to join NATO and vowed its membership would make the world’s most powerful military alliance stronger.Ukrainian President Volodymyr Zelenskyy addresses a crowd at Lukiskiu Square in Vilnius, Lithuania, during a NATO Summit, July 11, 2023.Odd Andersen | AFP | Getty ImagesUkraine has sought NATO membership since 2002. It is bordered by four NATO allies: Poland, Slovakia, Hungary and Romania. In September, Zelenskyy applied for a fast-track membership to join NATO. He has since visited several European capitals to garner support for Kyiv’s bid.Zelenskyy’s calls were overshadowed by the announcement on the first day of the summit that Turkish President Recep Tayyip Erdogan agreed to support Sweden’s bid to join the NATO alliance.Last May, Sweden and Finland began the formal process of applying to NATO, which requires approval from all 30 members of the alliance. In April, Finland joined the alliance. Following this summit, Sweden is set to become the group’s 32nd member.