As Russia confronts Ukraine, the definition of modern military intervention hangs in the balance.

U.S. leaders need to talk to the Russians, not threaten them.

Congressional Republicans are blocking crucial aid to Israel and Ukraine out of sheer servility to Trump.

Conflicts, though typically started easily, can be brutal, intractable, and difficult to end.

The country’s young people have been forced to make decisions much tougher than most adults are capable of. I feel some small sense of common cause.

Anything helps—we shouldn’t overthink it. But we should still, well, think it.

He is threatening to invade Ukraine because he wants democracy to fail—and not just in that country.

Ukrainians have fought not only for their own country, but also for Europe, giving the EU a powerful reminder of why it was founded in the first place.

Foreign policy in the United States was historically seen as having a bipartisan consensus on many of the most significant issues.

Did Obama’s refusal to strike Syria really give Putin the green light in Ukraine?