GEOFF BENNETT: The U.S. military has divided up the world into different regional commands and put a general or admiral in charge of planning and conducting military operations in each.

For the past two-and-a-half decades, the Middle East has been the busiest.

Nick Schifrin talks to one former commander who was in charge of the region during an especially momentous time.

NICK SCHIFRIN: Some 70,000 U.S. troops are stationed between Egypt in the West and Pakistan in the east, known by the military as Central Command.

It has historically been one of the most intense commands that the military has.

In the late 2010s and early 2020s, the U.S. killed the head of the Quds Force in Baghdad, the head of ISIS, and withdrew from Afghanistan.

And the commander of CENTCOM during that time has written a new book, "The Melting Point: High Command and War in the 21st Century."

That commander is retired General Frank McKenzie, who joins me here.

Frank McKenzie, thanks very much.

Welcome back to the "NewsHour."

GEN. FRANK MCKENZIE (RET.

), Former Commander, U.S. Central Command: It's good to be with you here tonight, Nick.

NICK SCHIFRIN: You wrote about your recommendation to kill Qasem Soleimani, the former head of the Quds Force.

And you point out that, at the time, Iranian proxies were firing off at U.S. troops across the region, and you believed that Iran felt it could act with impunity.

So take us back to that decision.

Why did you recommend the U.S. take that shot?

GEN. FRANK MCKENZIE (RET.

): This was in late December 2019.

Qasem Soleimani was entering Baghdad.

We had good intelligence that he was going to coordinate attacks on our embassy -- embassies beyond Baghdad, in locations across the region.

So, for me, at least, the risks of inaction were greater than the risks of action.

And we knew there would be risks if we struck Qasem Soleimani.

But if we didn't act, certainly, Americans would die.

It becomes a balancing test, and that was my recommendation.

And I thought it was the best thing we could do given the circumstances we were in at that moment.

I did not regret the decision at that time.

NICK SCHIFRIN: The strategic consequences of that strike.

Do you believe the strike had the desired effect?

And we now look at an Iran that has targeted Israel directly.

We are seeing proxies, including the Houthis, attack ships off of Yemen.

We're seeing Hezbollah launch an unprecedented number of strikes into Israel.

Do you believe that Soleimani's death had long-term strategic consequences that you were hoping they would?

GEN. FRANK MCKENZIE (RET.

): We struck Qasem Soleimani because of an immediate tactical problem, that he was going to be responsible for the deaths of Americans.

So we were looking at what would happen in the next 48, 72, 96 hours.

At the same time, we were also very much aware of what removing him from the battlefield would mean in the long term for Iran.

He was their best planner.

He was their best leader.

He was their best executor.

He is gone now.

And so, as a result, Iranian plans are not as well-defined.

And, frankly, they're not as effective as they would have been had Qasem Soleimani lived.

NICK SCHIFRIN: Some officials who look at Iran believe that today the proxies are actually more coordinated than they were in the past.

Do you see that?

GEN. FRANK MCKENZIE (RET.

): I do not.

I do not see that.

I see that in -- particularly in Iraq, it's difficult to get them all to sail in the same direction.

His successor has not been as effective as he was at doing it.

I don't want to say that it's a lot better, but I think we're in a better situation now that he is gone than if he had lived.

NICK SCHIFRIN: In the planning that led up to the strike, you actually rejected many different options that you detail in the book.

Why did you reject certain possibilities of striking him because of possible civilian casualties?

GEN. FRANK MCKENZIE (RET.

): We always try to minimize civilian casualties when we do these kinds of strikes.

And so the way we worked it out, it happened to be on Route Irish, which is... NICK SCHIFRIN: Right outside the Baghdad Airport.

GEN. FRANK MCKENZIE (RET.

): ... which an interesting thing, because Qasem Soleimani is responsible for the deaths of many Americans on Route Irish.

NICK SCHIFRIN: As Central Command commander, your area included Israel, and I want to look at the war in Gaza today a little bit and get your thoughts.

When you see how Israel conducts itself in Gaza and the challenges that Hamas as a group integrated into Gaza, and, of course, holding not only hostages, but also creating a terrorist infrastructure of tunnels underneath, how do you see Israel conducting its war?

GEN. FRANK MCKENZIE (RET.

): Hamas very cleverly integrated themselves fully into the civilian population.

So when you think about what's going on there, you should think, not only are the Israelis hostages, but actually the population of Gaza is a hostage held by Hamas.

So Israeli commanders are on the horns of a dilemma every time they want to take a strike or every time they need to advance because Hamas is literally hiding behind the civilian population in Gaza, which makes for very difficult decision-making for Israelis as they consider their options.

NICK SCHIFRIN: Israel has used 2,000-pound bombs, so-called dumb bombs, to target Hamas tunnels that go deep underground.

There's been a lot of criticism, including by the U.S. administration, on the use of those bombs to target those tunnels in extremely dense neighborhoods.

And the secretary of defense even said, you might have a tactical victory in certain respects, but a strategic defeat, i.e., strategic ramifications for regional partners or would-be partners of Israel who respond negatively.

Has there been, do you believe, strikes that Israel should not have taken?

GEN. FRANK MCKENZIE (RET.

): I'm not familiar in detail with the strikes Israel has taken.

I would agree with the secretary, though, that you have to be very careful.

Even if you have tactical success, sometimes, the price is not worth it.

But that's a decision that Israel is going to have to make.

They're going to have to look at the proportionality of the strike and weigh those independently.

NICK SCHIFRIN: You talk about Iran's missile inventory in the book, which is the largest in the region.

And you write: "By 2019, Iran had 50 or so ballistic missiles capable of reaching Tel Aviv and the clear ability to gain overmatch against their neighbors," meaning the ability to overwhelm air defense.

In April, Iran fired more than 300 drones and missiles at Israel and caused very little damage.

What did you see in the failure of that attack or apparent failure of that attack that perhaps surprised you?

GEN. FRANK MCKENZIE (RET.

): I thought they would be more effective, actually.

I just -- I looked at Iran for a long time.

They now have many, many hundreds of missiles that can reach Israel.

But they're -- they have a problem.

They can't fire all those missiles at once.

Now, a lot of things went right for Israel, but, most importantly, they're in the central region.

There are procedures in place to exchange information.

And while nascent, there is a path forward here.

NICK SCHIFRIN: Finally, Afghanistan.

You have said publicly and you write in the book that you argued against a full U.S. withdrawal and that the U.S. would not be able to conduct counterterrorism if the U.S. fully withdrew from Afghanistan.

And the National Security Council, in response to some of your public criticism recently said this: "We have demonstrated we do not need a permanent troop presence on the ground in harm's way to remain vigilant against terrorism threats."

Do you believe that's correct?

GEN. FRANK MCKENZIE (RET.

): I do not.

I believe that our ability to see into Afghanistan is very limited.

I believe we have taken one strike since 2022 into Afghanistan.

And I believe ISIS -- and I refer to the Central Command commander's testimony of this spring and other intelligence officials who have testified to the fact that ISIS-K is growing.

They do aspire to attack us here.

Our ability to thwart that planning in Afghanistan is quite limited.

The attack in Russia, Moscow, recently is an example of that.

And so I think we should expect this threat to rise.

So I just have a different view.

I understand that others may take a different view, and I appreciate that.

NICK SCHIFRIN: Frank McKenzie, thank you very much.

GEN. FRANK MCKENZIE (RET.

): Thanks, Nick.