Now, an unlikely pair of countries are coming to assist the embattled government -- the United States and Iran.

While U.S. advisers are on the ground assisting security forces, Iraq is increasingly relying on Iranian-backed Shiite militias to stave off radical Sunni ISIS militants -- especially around the capital.

Why we should care:

Former U.S. Vice President Dick Cheney said the crisis in Iraq now involves throngs of foreigners -- possibly including Americans.

"One of the problems you've got now is a caliphate that includes part of Syria, part of Iraq, and you've got literally thousands of jihadist wannabes flooding into that part of the world from Europe -- some of them probably from the United States -- who want to participate in that conflict," Cheney told CNN's Jake Tapper.

"It's a threat to us, to the United States, not just to that part of the world."

LIBYA

A free-for-all

Nearly three years after Libyan rebels overthrew a longtime dictator, the country is no closer to lasting stability.

The civil war that culminated in Moammar Gadhafi's 2011 death has given way to warring militias fighting over Tripoli's international airport.

At least 90% of the planes there have been damaged, and it would cost hundreds of millions of dollars to repair them, the government said.

Maintenance buildings are destroyed. So are fuel tanks and trucks. Even the control tower has been hit.

The chaos in the capital is so dire now that officials are considering asking for international troops -- even though the government is virtually powerless and has very little influence on what's happening on the ground.

Not only is government is weak, but militias actually outnumber and outgun its security forces.

Why we should care:

The U.S. State Department said the fighting could lead to widespread conflict.

"We affirm our support for Libya's democratic transition and urge the seating of the new Council of Representatives as soon as possible," the State Department said. "We stress the vital role Libya's Constitution Drafting Assembly plays in building the new country for which Libyans sacrificed so much during the revolution."

And of course the U.S. is still trying to figure out more details on the 2012 attack that killed four Americans at a U.S. diplomatic compound in Benghazi, including U.S. Ambassador Chris Stevens.

GAZA AND ISRAEL

Retaliation and recrimination

What was supposed to be a cease-fire between Israeli forces and Palestinian militant group Hamas this week now seems like a joke.

Rockets fired by Hamas on Tuesday were quickly matched by airstrikes from Israel.

And so the exchanges continue.

Now, a leading member of Hamas says he's not opposed to peace -- but says there needs to be more compromise.

"We hope we can achieve a cease-fire -- but a cease-fire which can protect the Palestinians and guarantee that there will be no violations," Hamas spokesman Osama Hamdan said.