David Armitage's book tracks changing definitions of civil war, from Ancient Rome to the American Civil War to now.

His threats against North Korea expose the many dangers of the White House's post-9/11 powers. Here's what Congress must do.

The standoff on the Korean Peninsula is tense, but stable—unless the American president disrupts it.

His leftist apologists in the U.S. media aren't just blind to Russia's election meddling, but to Putin's xenophobia and homophobia.

Will Trump's bluster spark a war with Iran?

The class responsible for the lucrative rush to war can literally buy its way out of annihilation, thanks to the boom in luxury bunkers.

Despite Trump's campaign rhetoric, his hawkish stance increasingly resembles Hillary Clinton's—and it's stirring fears of a major war.

What might countries accomplish now that they can't rely on America?

In Western Sahara, 165,000 refugees are still fighting for their freedom.

Nixon was smart and calculating. Trump is just ignorant and incompetent.

The president is becoming a typical right-wing Republican, thereby preserving a flawed status quo.

Dave Grossman teaches police officers to think like "warriors." But is the rise of a militarized mindset turning black citizens into targets?

The missile attack on Syria shows how the president has caved to the Pentagon—with deadly consequences for U.S. foreign policy.

New military recruits train for battle against their powerful neighbor.

The president-elect joins a long minority tradition within the GOP of opposition to European alliances, and it could lead to global conflict.

His reaction to the truck attack in Berlin, and his disinterest in daily intelligence briefings, show a reckless indifference to Americans' safety.

His lies are a problem, but his belligerence is worse: It could start a war.

Exxon Mobil CEO Rex Tillerson could serve as a check on hawkishness.

Here's how Donald Trump can help—without a full-scale intervention.