GEOFF BENNETT: Today, the British and German foreign ministers visited Israel and urged the government to show restraint.

But Prime Minister Benjamin Netanyahu said only Israel will decide how to respond to last weekend's unprecedented Iranian missile and drone attack.

And Israeli officials have indicated they will respond.

Nick Schifrin speaks to experts now about what that action might look like and how it will affect the region -- Nick.

NICK SCHIFRIN: For decades, Geoff, Israel and Iran have fought one another in the shadows and through proxies, until Saturday night, when Iran launched the first ever state-on-state attack between these two countries, with more than 300 missiles and drones flown from Iran toward Israel.

That attack was a response to an Israeli strike in Damascus that killed senior Iranian commanders.

What will Israel do next and what might Iran do in response?

We get two views.

Eric Edelman served as U.S. ambassador to Turkey and was undersecretary of defense for policy in the George W. Bush administration.

He's now at the Center for Strategic and Budgetary Assessments, a research institute.

And Vali Nasr was a special adviser in the State Department during the Obama administration.

He's now a professor at the Johns Hopkins School of Advanced International Studies.

Eric Edelman, Vali Nasr, thanks very much.

Welcome, both of you, back to the "NewsHour."

Eric Edelman, let me start with you.

As Geoff just said, this attack by Iran was unprecedented.

Do you expect Israel to retaliate in a significant kind of way?

And should they?

ERIC EDELMAN, Former State Department and Defense Department Official: Well, I think Israel has no choice but to respond, Nick.

This was, as you said, unprecedented, but the scale of this attack is what's really sort of breathtaking, very large attack with both ballistic cruise missiles and UAVs, clearly meant to overwhelm Israel's layered air defenses.

And I think it is impossible for Israel not to strike back in some way.

But Israel is in a quandary, because part of its success in inflicting a pretty humiliating defeat on what is one of the main tools of coercion available to the Iranian regime was through the work of its allies, including the U.S. coordinating a lot of efforts with CENTCOM, also the U.K., France, but also Arab partners.

And Israel doesn't want to alienate them.

So the calls for restraint are clearly having an impact.

The Israeli war cabinet has met, I think, four times now trying to determine exactly how to respond.

And it's a difficult decision for them.

NICK SCHIFRIN: Vali Nasr, is that how you see this strike, breathtaking scale designed to overwhelm Israeli and allied defenses?

VALI NASR, School of Advanced International Studies, Johns Hopkins University: I think Eric's analysis is actually correct.

So what we have been seeing is that the rules of the game have been significantly shifting with every attack and counterattack.

So Israel hitting the consulate in Damascus was viewed by Iran as sort of a new sort of red line that Israel crossed.

Iran's attack on Israel is significant, not only in terms of the number of missiles that were used, but that it was also launched from Iranian territory.

It was done in a brazen way.

And the doctrine that went with it is that, from now on, if you attack Iran, we attack you directly.

Now, how Israel responds to this -- and I do agree with Eric that, both for domestic political reasons and for strategic reasons, it's very, very difficult to see a scenario in which Israel would not react, could also, if you would cross, another red line.

So we're in an escalatory cycle where the rules of the shadow war are no longer holding.

And with each of these attacks, we may be crossing a new Rubicon, and that eventually can open - - end up in an open conflict.

NICK SCHIFRIN: But, Eric Edelman, I mean, there are people in Israel, including inside the war cabinet, who are arguing for a much more robust and immediate response.

And they argue that anything short of a direct military strike by Israel on Iran will allow Iran to have reset deterrence and not -- and prevent Israel from creating their own new line.

ERIC EDELMAN: Well, I mean, I think that Israel has many, many tools at its disposal.

And one of the things I think that's asymmetry here is that the very complex, layered defense that Israel has available to it is not something that Iran has.

I think Israel has lots of ways, including nonkinetic ways with cyber, to inflict real costs, impose real costs on the Iranian regime in a way that does reset deterrence without actually getting into the kind of escalatory spiral that Vali was discussing, which I agree is a possibility.

But, right now, I think this was a very - - should be a very disturbing defeat for the Iranian regime.

The fact that I think that they're concerned about it has been demonstrated by the crackdown on domestic dissent that we have seen in the last 48, 72 hours.

And, right now, it's not even clear that they could launch a second volley, since they may have used up a lot of their medium-range ballistic missiles in the first go-round.

And the failure rate may have been as high as 50 percent.

So if you're sitting in Tehran, I think you might be more worried about an escalatory cycle than Israel is right now.

NICK SCHIFRIN: Vali Nasr, two U.S. officials did confirm to me that the failure rate was 50 percent.

But in terms of what Iranian government is saying, they are saying that they could actually go bigger next time.

And President Raisi specifically said that even a small attack by Israel on Iran would yield a larger strike on Israel.

Is that bluster or is that real?

VALI NASR: I think it's both.

In other words, definitely, there's bluster, but there's also definitely very tough rhetoric in order to dissuade Israel from doing something that would then force the Iranians to escalate.

But I would say that exactly the ambiguities that exist here, what can the Iranians do, how afraid are they, would they react, at what level they react, is exactly why Israel is pondering its response and why you have two foreign ministers visiting Israel in order to ask Israel to restrain itself.

But, partly, this is not entirely a military issue.

It's not a question of just what fail rate Israel's missiles had, but the way in which this crisis over the last 10 days impacted global markets, impacted psychologically Israel, economically, but also the way in which the United States and Europe reacted to the urgency of the situation basically does give Iran a certain leverage here.

In other words, once Israel attacks Iran, we don't know when Iran would react, but we may go through another 10 days, 15 days of this sort of thing.

And then, if the Iranians decide to react, and then Israel reacts to Iran's reaction, essentially, Israel and Iran are not -- no longer the only two parties that are affected by this crisis.

The global economy, the Arab governments around them, Europe and the United States are affected, and they're quite worried.

And that's also a factor that's playing in here as well.

NICK SCHIFRIN: Eric Edelman, very quickly, because we only have about 45 seconds, the U.S. is trying to urge Israel not to strike back at all.

And they're urging sanctions internationally.

They're talking about that air defense coalition expanding.

Could that reassure Israel not to strike?

ERIC EDELMAN: I think that what I have heard from U.S. officials is that they expect that there will be some retaliation by Israel.

Exactly how it goes, I think nobody really knows right now.

And there has been, as Vali was suggesting and as you have suggested, Nick, some hesitation the Israeli side about how far to go.

NICK SCHIFRIN: Yes.

ERIC EDELMAN: But I think you're going to see some response.

NICK SCHIFRIN: And, Vali Nasr, does that necessarily mean exactly what you were just worried about, another round and more weeks of concern for the whole region?

VALI NASR: Well, it depends on what the nature of that response is.

And then we're going to see all these European diplomats, U.S. through back channels, Arab diplomats turn their attention to Tehran to try to preach the same thing to the Iranians to - - not to react to the Israeli attack.

NICK SCHIFRIN: Yes.

Vali Nasr, Eric Edelman, thanks very much to you both.

ERIC EDELMAN: Thank you.

VALI NASR: Thank you.