Following President Barack Obama's Oval Office address Sunday night, award-winning foreign correspondent Rukmini Callimachi added her expertise to the conversation in a 19-tweet marathon that could easily comprise the syllabus of an ISIS 101 course.

Callimachi, who covers al-Qaida and ISIS for the New York Times, shed light on the biggest problems not addressed in the president's four-pronged plan to combat the Islamic State.

But first, the reporter praised the president for "do[ing] his homework" in acknowledging that sending troops to Iraq and Syria would be playing into the hands of ISIS, who, she said, is desperate for the U.S. to bring the war to them.

"We should not be drawn once more into a long and costly ground war in Iraq or Syria," the president said in his address. "That's what groups like ISIL want. ... They also know that if we occupy foreign lands, they can maintain insurgencies for years, killing thousands of our troops, draining our resources and using our presence to draw new recruits."

1/Obama has done his homework when he says ISIS wants us to start a ground war, and will use our occupation of a foreign land to recruit

2/ ISIS propaganda is rife with references to scriptural prophecy regarding the last great battle of our time which will begin when

3/ The "Romans" (us) invade Dabiq, a town that still exists today in Syria. In scripture that battle sets the stage for the end of times

4/ leading to a showdown between "Muslims" (they think this refers only to them) and their enemies, in which the enemies are vanquished

5/ Remember it was in Dabiq that ISIS killed US hostage Peter Kassig, a former U.S. Army Ranger, as a way to underscore this point

6/ While it's hard to get our heads around this, I have spoken to enough ISIS fanboys & members by now to believe that they mean this

7/ ISIS *wants* U.S. boots on the ground, and wants us to engage them militarily. It would do wonders for their recruitment pitch

Eight tweets in, Callimachi asks the question that should take priority in the Situation Room.

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8. Question is: Can fight against this group be won from the air & via proxy forces on the ground, ones which are divided ethnically?

Callimachi cites her firsthand accounts from Syria and Iraq, where she witnessed three factions of Kurdish militia fighting ISIS.

9/ Here is what I saw in Hasaka, Syria in July where I was embedded with YPG militia fighting ISIS & what I saw in Sinjar, Iraq last month

(The PKK, also known as the the , is a left-wing, militarized political party . The YPG — or the — on the other hand, is the army equivalent for the Kurdish Supreme Committee, the de facto government in the part of Syria regarded by many as Kurdistan. The Peshmerga, in northern Iraq, are the most historically rooted of these three, dating back to the late 1800s.)

10/ where I was embedded with the PKK and with the Peshmarga, two more local forces fighting ISIS: In both places ISIS folded quickly

The success of these forces, the reporter reminds, is not only achieved through military and political cohesion, but also continued air strikes from the U.S.

11/ In Hasaka, I saw frontline jump several miles in a few days; In Sinjar, I saw airstrikes & local forces take city in 48 hours

12/ But here's the rub: The proxy forces *only* succeeded because of heavy U.S. air support & air support will need to continue indefinitely

13/ If we let up the freed areas will be reinfiltrated. Already there are reports that Hasaka, which was declared liberated when I was there

14/ has been re-infiltrated by ISIS cells. Second big problem: The proxy forces fighting ISIS are nearly all Kurdish (YPG, Peshmarga, PKK)

15/ And they will only fight for historically Kurdish areas. Last month, I went to a sandbagged position overlooking the city of Mosul, Iraq

Callimachi said she witnessed this current lack of cohesion on the ground. While these various factions may all be pro-Kurdish, that ultimately translates into different goals, in different territories, as exemplified by one Peshmerga commander who would only protect half of key city Mosul, in northern Iraq, "because that is the ethnic faultline, and as a Kurdish commander he did not think it would be appropriate to go further in," she tweeted.

16/ Mosul was so close, were I wearing running shoes I could have jogged there and back. But the Peshmarga commander holding the position

17/ explained to me that when invasion of Mosul occurs (believed to be many months away) he would only fight to roughly halfway in to city

18/ Why? Because that is the ethnic faultline, and as a Kurdish commander he did not think it would be appropriate to go further in.

While Kurdish forces are responsible for much of the ISIS pushback on the ground, she said, here's the kicker: The most crucial cities, strategically, for winning this battle are not primarily Kurdish — they're Sunni.

19/ The cities that need to be taken back (Mosul, Raqqa etc) are mostly Sunni, not Kurdish, and the U.S. has yet to find a Sunni proxy force

Having spent years covering this arena, Callimachi is well-positioned to understand the complexities and intricacies of this scattered war. She wrote extensively on the operations of extremist Islamic terrorist groups — from al-Qaida's financing through European ransoms to the experience of ISIS hostages — and has spent substantial time in territories relevant to this situation.

In short, those tasked with ensuring the defeat of ISIS would do well to read Callimachi's Twitter feed.