The main battle tanks that the United States and Germany have agreed to provide Ukraine will help its forces punch through Russian fortifications and retake lost territory.

The collapse of the Cold War–era nuclear arms treaty signals trouble for U.S.-Russia relations, European security, and nonproliferation efforts.

The first summit between Joe Biden and Vladimir Putin eased some of the tension in the fraught U.S.-Russia relationship. It also laid bare the difficult path ahead to resolving differences on many is…

Russia is targeting Ukrainian cities and civilian infrastructure with Iranian-made loitering munitions. Are these weapons effective in shaping the war? 

Mounting frictions between the two sides appear to be part of China’s efforts to disrupt the ties between South Korea and the United States but could end up drawing the two allies even closer.