The Balkan policy of the Biden administration is undoing much of what then-Sen. Joe Biden accomplished over 20 years ago. During the 1990s, with strong bipartisan support, the United States and NATO ended the Yugoslav Wars through tough diplomacy and direct intervention. Washington also recognized all states that emerged from the defunct Yugoslav federation and made sure that no nation would dominate others. Two decades later, placating an autocratic regime in Serbia is undermining the foundations of western Balkan security and threatening to push the region toward new armed conflicts.