Tom Bowman

President Trump's National Security Adviser Michael Flynn has resigned amid allegations he inappropriately talked about U.S. sanctions in December with a Russian official.

President Trump tweeted criticism of Sen. John McCain, who called the Yemen raid a "failure." Trump said McCain "doesn't know how to win anymore" and called it a "winning mission." But is that true?

The U.S. commander in Afghanistan, Gen. John Nicholson, tells the Senate that the U.S.-led mission is in a "stalemate." He says the Taliban gained 15 percent more ground in 2016 and that "a few thousand" more NATO trainers are needed.

Witnesses tell NPR about the raid, the military's first under President Trump. It resulted in deaths of a Navy SEAL and civilians. A CENTCOM investigation is underway, but similar raids could follow.

The U.S. military has acknowledged that civilians were killed in last weekend's special operations raid in Yemen. Other questions continue to swirl, however, including whether American forces' surprise was blown and whether their target was indeed an al-Qaida terrorist as they believed.

A U.S. serviceman was killed in the raid that also killed some 14 al-Qaida terrorists. News of the raid followed orders from the White House, including one that changed the National Security Council.

President Trump visited the Pentagon for the first time on Friday. He conducted a formal swearing-in for Defense Secretary Mattis and met with the Joint Chiefs of Staff.

President Trump has revived discussion about implementing military "safe zones" in Syria, an idea from the early days of the civil war. But fencing off areas in Syria might not make sense given the current reality of the conflict, and it would be a challenge for the U.S. and its allies to put them into place.

President Obama convened his final press conference in office on Wednesday less than a day after commuting the prison sentence of convicted leaker Chelsea Manning. Obama was expected to face questions about his decision to grant clemency to Manning, who gave hundreds of thousands of military and diplomatic files to WikiLeaks.

President Obama commuted the prison sentence of ex-Army Private Chelsea Manning, who gave a trove of secret military and diplomatic files to WikiLeaks. Obama's action has angered many in the military.

Retired Marine Gen. James Mattis faces the Senate Armed Services Committee on Thursday for his confirmation hearing to become President-elect Trump's secretary of defense. The popular former four-star commander is expected to face questions about ISIS, Iraq, Afghanistan and other tough issues, but appears likely to be confirmed.

George Marshall was the last general nominated for defense secretary and he needed a waiver from Congress. We take a look at Marshall's Senate hearing in 1950. Donald Trump's pick also needs a waiver.

The officers, posted to the U.S. on exchange tours, are stranded after a July coup attempt in Turkey that has led to deep purges. They risk prison if they go home. Washington is in a tough position.

President Obama gave one of his final news conferences as president on Friday. Here, NPR reporters provide context on five different Obama quotes.

Michael Flynn was a celebrated Army intelligence officer, though he was forced out of the Defense Intelligence Agency. He's known for energy and smarts, and for sharing conspiracy theories.

President-elect Donald Trump has already picked two former generals, Michael Flynn and James Mattis, for top positions and is considering at least one more, David Petraeus.

At a rally in Cincinnati on Thursday night, Donald Trump said he would select retired Marine Corps Gen. James Mattis to lead the Defense Department, filling a key role in the incoming administration.

Speaking to a crowd in Cincinnati where he celebrated his win in Ohio, Trump compared Mattis to World War II Gen. George S. Patton and said a formal announcement of his nomination would come Monday.

The retired general was one of the first ex-military officers to back Donald Trump. His brazen comments and partisan political work trouble some of his former colleagues.

As Iraqi forces move into Mosul, they face resistance from ISIS fighters. In Syria, local forces have started an operation to recapture Raqqa, the defacto capital of ISIS.