What does the U.S. do about ISIS?

On Tuesday, he spent time answering your questions about the strategy for defeating the terror group. Below are highlights from the chat (note: questions have been abridged for this post). You can read the full Q&A here.

1. Why aren't many nations saying to go in full force and wipe ISIS out? -- Cathy C.

Counter insurgency operations don't succeed over the long-term unless the home government feels responsible for solving the problem. At some point, the training wheels have to come off. The Iraqis have to carry the load.

2. Why aren't other countries helping the United States defeat ISIS? -- Philip O.

Other countries are assisting. Here's the complication: the U.S. has tremendous capability. When you have that kind of capability, you have a lot more options to exercise power over seas. We are involved partly because we have so much more capability than anybody else.

3. Let the countries that have ISIS deal with them. We need to protect America -- Douglas G.

The problem with this approach is that if ISIS cements control, they will start thinking about expanding their reach to Europe and the United States. Stick with the Iraqis in the fight or risk an expanded ISIS threat down the road.

4. Why don't we start attacking from the air where we can do more damage per strike and get rid of more ISIS members quicker? -- Chris B

One of the biggest problems in an air campaign like this, is that you're fighting urban insurgents. Every urban strike risks civilians and gives ISIS a potential propaganda win. Urban counter-insurgency from the air requires a ground component. That's why the Iraqis have to fight.

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5. Can we leave it up to Saudi Arabia to defeat ISIS? -- Tom M.

Saudi Arabia does not have the same capability as the U.S. They can't do this. We have no good options, but the worst option would be to abandon the Iraqis and leave the field to Tehran.

6. Do you think the Obama administration is reluctant to put boots on the ground because of political backlash? - John M.

You can choose to make this political if you want. Or you can choose to study counter insurgency. The Iraqis can win this, the U.S. can't. Counter insurgency does not succeed if the home government is too weak to fight.

7. Why keep waiting? There is only one thing we can do and that is go to war with them.

I disagree. We are helping the Iraqis contain them. ISIS will accelerate their demise in the meantime. They can intimidate; they can't govern, that will hurt them in the long-term.

8. How do we protect our homeland? -- Malik S.

First we need to try to find the most senior ISIS members who are involved in plotting attacks against America, pinpoint operations in other words. Then help the Iraqis long-term without giving them the sense that we can substitute for them.

9. Where does ISIS get their weapons? -- Mike-Wayne T.

A lot of them are coming from captured government stock. Weapons aren't the key here though: leadership, ideology, recruitment, the will of the Iraqi military -- these are all more important factors in judging this campaign.

10. Why haven't we been able to stop the flow of money that supports ISIS? -- Mickey W.

First, they can generate their own funds. For example, taxes in the areas they control. Stopping 100% of international money flows is virtually impossible. Money will not allow ISIS to survive. It'll only survive if it can learn to compromise with local populations.

11. Why do you think more and more people are sympathizing for ISIS? -- Elias D.

1. The message is available to everybody via social media. 2. The location that is Syria is easily accessible. 3. ISIS has been around long enough to generate momentum. Bad combination.

12. If everything went "our way" in the next 6-12 months, do you think ISIS could be defeated by this time next year? -- Noreen M.

No, they will not be defeated in that time frame. What has to happen is that local villagers have to rise up. Right now, we are depending too much on the government.

(CNN)