President Obama announced on Thursday that he had authorized US airstrikes against the extremist group ISIS in Iraq if it threatened the Iraqi Kurdish capital of Erbil or the ten thousand or more Yazidi minority civilians besieged on Mount Sinjar, both in northern Iraq. He also announced the US would airdrop emergency humanitarian supplies over northern Iraq to help those Yazidi. That is a big step for a president who has worked so hard to pull the US out of Iraq.
How did things get so dire in Iraq? Who is ISIS and how have they managed to seize huge swathes of territory there, as well as in Syria? This video explains how we got to this point, and why ISIS has been so unstoppable in Iraq:
Two big things have happened much more recently to make the crisis bad enough that Obama might send air strikes.
First, ISIS pushed into previously-secure northern Iraq, which is controlled by the country's ethnic Kurdish minority. Kurdish Iraq was considered so secure that the US evacuated its Baghdad embassy staff to the Kurdish city of Erbil, where they still are, putting the Americans under threat from ISIS. That's a big part of why the US is launching air strikes.
Second, ISIS sent at least ten thousand civilians from the ethno-religious minority group Yazidi fleeing from their homes and onto the nearby Mount Sinjar. They are still there and have no regular access to food or water; they can't descend the mountain because ISIS will slaughter them. The American humanitarian airdrops will bring the Yazidi water and perhaps food. US airstrikes could also push ISIS back from Mount Sinjar if the US believes ISIS is threatening the Yazidi there.
But remember that all of this goes back to the Iraq War, and al-Qaeda's rise there, and to the more recent Syrian civil war that gave ISIS a base of operations.