TOKYO -- In January 2012, then-U.S. President Barack Obama outlined a major shift in Washington's national defense objectives: an end to its two-front-war strategy.
"America's not the world's policeman," he would later say.
Tensions over Ukraine and Taiwan pose challenges for a weakened Washington

U.S. President Joe Biden, Japanese Prime Minister Fumio Kishida and Russian President Vladimir Putin. © AP
TOKYO -- In January 2012, then-U.S. President Barack Obama outlined a major shift in Washington's national defense objectives: an end to its two-front-war strategy.
"America's not the world's policeman," he would later say.