Now that the US is bombing the Islamic State (ISIS) in Iraq with a campaign narrowly targeted to support the Kurdish military, or peshmerga, you may find yourself wondering why it is that Iraqi Kurds have their own army separate from the rest of Iraq. Or why the US cares so much about protecting Kurdistan, or how it got its special status in the first place. What's happening right now is part of a much longer story for the Kurds, one involving a century-long struggle for independence that may be nearing a turning point.

Here's a guide for what you need to know about the Kurds, why the US is so eager to protect them, and how they got to this unique position within the Middle East.

1. The Kurds have a unique and difficult history in the Middle East

The Kurds are often referred to as one of the largest ethnic groups in the world with no state of their own. But there's an interesting history to that identity. "It is extremely doubtful that the Kurds form an ethnically coherent whole in the sense that they have a common ancestry," scholar David McDowall writes in his widely acclaimed history of the Kurdish people. McDowall thinks the Kurds come from a mish-mash of ancient Indo-European, Arabic, and Turkomen tribes (mostly the first).

That said, he thinks Kurdish ethnic identity, like many group identities, is pretty modern: "the Kurds only really began to think and act as an ethnic community from 1918 onwards." So the Kurds have been in the Middle East for a very long time, but they haven't necessarily thought of themselves a big, ethnically unified group until recently. That turns out to be important for how Kurds interact with the rest of the region (more on this later).

Regardless, the Kurds clearly think of themselves as a distinct ethnic group today, and the people who live near them tend to agree. As this map of areas with significant Kurdish populations below shows, most Kurdish-inhabited territory is in either Iraq or Turkey, with communities in Iran and Syria as well:

The most populous Kurdish community is in Turkey — about 13 million. There's between seven or eight million in Iran, about five million in Iraq, and somewhere between 2 and 2.5 million in Syria. These large numbers, together with a distinct sense of Kurdish ethnic and national identity, make the Kurds really important players in the region and especially in northern Iraq.

2. Iraqi Kurdistan has gotten really close to independence

The Kurds have been struggling for independence in all four of those countries. But they have a special deal in Iraq that they have nowhere else in the world: territory they actually govern semi-autonomously from the central Iraqi government. Iraqi Kurdistan is defined as the three provinces — Dohuk, Erbil, and Sulaymaniyah — in the raised northeast part of this map:

An independent Kurdistan has been a dream for the region's Kurds for decades. Each of the largest Kurdish communities have faced serious oppression; an independent Kurdistan would be both a safe haven and a fulfillment of a long-running campaign for real Kurdish self-determination.

Iraqi Kurdistan is the closest thing to a Kurdish state. To understand how it got that way, you have to go back to at least 1988 — to Saddam Hussein's genocidal response to a Kurdish rebellion. Rather than granting the Kurds autonomy when they rebelled for it, Saddam lined up Kurdish civilians and executed them. He also used chemical weapons against Kurdish communities. The Anfal campaign — Saddam cruelly named his slaughter after a verse in the Koran — claimed somewhere between 50,000 to 180,000 Kurdish civilian lives.

At the end of the 1991 Gulf War, the Kurds rose up again. Once again, Saddam viciously put them down. The international community didn't stop Saddam, but it did intervene after the fact to set up a "safe zone" for Kurds in part of Kurdistan, where they could live in peace without fear of Saddam's army. Kurdish militias eventually expanded the zone to what it is today, and the Kurds set up a government with de facto autonomy.

Then the US invaded in 2003, toppled Saddam, and replaced him with a government that formalized the Kurdish semi-autonomous government. But in practice, Kurds have even more autonomy than they've got on paper.

"De facto, the way it works is that the [Kurdistan regional government] is a confederal region, not a federal one," Kirk Sowell, a risk analyst and expert on Iraqi politics, says. "It has its own military, foreign policy, etc." In other words, Iraqi Kurdistan is significantly more autonomous than an American state, but still not quite its own country — yet.

3. Kurdistan still depends heavily on both the Iraqi and Turkish governments, despite having a ton of oil

You might wonder, given the Kurds' long history of persecution and deep desire for a state, why they haven't just declared independence from Iraq already. There are a number of reasons, including American opposition, but a big one is oil. They don't yet produce enough to be economically self-sufficient (but they might), and they don't have legal authority to sell it directly on the market.

Under the current arrangement, the Baghdad government is supposed to handle Kurdish oil sales. They then take the proceeds and divvy them up among the different regions. Kurdistan is supposed to get 17 percent of the nation's oil sales, but Kurdish leaders say they're given less than that.

The Kurds survive on that oil money. But this also makes them dependent on Baghdad. So they've been testing out the waters on selling oil directly, largely to Turkey. In early 2014, Baghdad retaliated, and started cutting off payments to the Kurdish government from the oil-sharing agreement.

Kurdistan survives on payments from the Iraqi central government

This is the financial barrier to Kurdish independence: the Kurds lack the infrastructure to export enough oil to make independence financially advantageous.

"Four years from now, I think [Kurdistan] will be viable," Sowell says. "But right now, they don't have the infrastructure necessary to replace the roughly $1 billion a month they get from Baghdad."

They also really depend on Turkey. The Turks used to be quite hostile to Iraqi Kurdistan, worrying both about its own Kurds wanting independence as well as Iraqi Kurdistan becoming a base for the Kurdistan Worker's Party (PKK), a quasi-Marxist militant group that has bombed targets in Turkey in the name of Kurdish self-determination.

However, Turkish Prime Minister Recep Tayyip Erdogan reversed course, building up trade ties with Iraq's Kurds. The Turks "have effectively turned Kurdistan into a colony," Sowell says. "Go to a grocery store in Erbil [Kurdistan's capital], and most of the products are Turkish ... [an independent Kurdistan] would be just as dependent [on Turkey] as they are on Baghdad."

4. Kurdish politics are divided between two groups — and two families

There are two major parties inside Kurdistan, the Kurdistan Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK). Each is led, at the moment, by a member of one of Kurdistan's two leading families, the Barzanis and the Talabanis. This division essentially defines internal Kurdish politics.

For a while, the KDP was the only major Kurdish party operating in Iraq. In 1975, the PUK broke off, led by Jalal Talabani and five others (including the current Iraqi president, Fuad Masum). Today, they're strong in different areas of Kurdistan: the KDP in the north, and the PUK in the south. There doesn't appear to be much of an ideological disagreement: as Missouri State University Professor David Romano writes, "the PUK itself came in practice and behavior to resemble the KDP so much that the average Kurds were often unable to specify a single policy or ideological disagreement between the two."

Still, Kurds' political split can cause serious problems. In the 1990s, it degenerated into open warfare between armed groups loyal to each party. It got to the point where, in 1996, the KDP asked for Saddam's help in rooting the PUK out of Erbil, which it controlled. This has ended, and the two parties have formed a sort of tactical alliance, but the point is that the Kurds aren't totally united. And neither is their government, or their military.

5. The Kurdish military is strong, but not as strong as many think

Kurdish soldiers are called peshmerga, which translates roughly as "those who face death." They have a pretty fearsome military reputation, which is somewhat deserved: they're far more competent than the Iraqi central military. But the fact that ISIS was beating them back before the US got involved (though Iraq's central military had collapsed against ISIS much more rapidly) reveals some serious limitations.

There are somewhere between 80,000 and 240,000 peshmerga — it's hard to say for sure. Those numbers are significantly higher than even the high-end estimates of ISIS' strength, so you think that they'd be able to defend Kurdistan easily from an ISIS incursion.

"The national security adviser is Masrur Barzani, the son of the president"

Two problems. First, they aren't that well armed. "They had to get the weapons from former Soviet states that were selling them, sort of like army surplus," Sowell says. ISIS, meanwhile, had captured US-made Iraqi army equipment and heavy weapons acquired in Syria. The US has now begun direct arms transfers to the peshmerga, so the balance of arms may shortly change.

The second problem is politicization. "They're definitely more disciplined and competent than the Iraqi military, but that's a low bar," Sowell says. "All aspects of the Kurdish government are heavily politicized, and this is more true of the security services than any other. Every peshmerga unit is headed by the a member of the politburo of the PUK or the KDP."

Sometimes, this politicization borders on the absurd. "The national security adviser is Masrur Barzani, the son of the president," Sowell notes. "Any military where the president's son gets to head the national security council and political allies get to head divisions is not going to be the most effective."

6. In the short term, the Kurds are in trouble, but in the long run, they may gain from the current crisis

Iraqi Kurdistan looks like it's in a lot of trouble right now. ISIS has made real gains inside Kurdistan and Erbil is running out of money. But these problems aren't insurmountable, and Kurdistan stands to gain a lot if it can successfully repel the ISIS incursion.

The financial problem is that Iraqi Prime Minister Nouri al-Maliki was withholding payments to Erbil. He was punishing the Kurds for their attempts to sell oil to Turkey directly, skirting the national revenue sharing agreement governing oil sales.

But, now, Maliki has lost the support of his own party, and is essentially a lame duck. His likely successor, Haider al-Abadi, needs to put together a government to become the next prime minister — and Kurdish political support could put him over the top.

"Assuming Abadi is willing to renew budget payments to Erbil," Sowell says, "I imagine the Kurds, because they're so weakened, would agree to whatever formulation you have to come up with to get that money flowing again." So the Kurds will likely get their payments back quickly.

And then there's the seizure of Kirkuk

Since the US intervention, the peshmerga have retaken some of the towns ISIS had seized. It's possible ISIS will hold onto the territory they've taken, but on-the-ground reports make it sound as if the momentum is flipping to the Kurds. "They're not going to hold this ground," Sowell says of ISIS. "Their fanaticism is getting the better of them."

And then there's the Kurds' seizure of Kirkuk. The plurality-Kurdish city is right next to an oilfield that contains an estimated 10 billion barrels of oil — it currently exports about 400,000 per day. The Kurdish government has long argued that Kirkuk is part of Kurdistan, but it's just outside of Kurdistan's currently recognized borders. The Iraqi government wants to keep it in non-Kurdistan Iraq so it can keep all of the oil revenue.

In June, as Iraq's military fought against the invading ISIS forces, the Kurds seized Kirkuk, arguing that they needed to do this to keep it secure. In the long run, it's an extraordinary prize, as it greatly increases the Kurdish government's oil production capabilities. That makes independence far more viable in the long run. "It's like taking East Jerusalem in 1967," Sowell says.

"Right now, they need money," Sowell says of the Kurds. "But in the long run, they'll be stronger."