GEOFF BENNETT: Today, the U.S.

launched what the Trump administration is calling an economic D-Day against Iran.

Operation Economic Outcast, as it's called, threatens tougher sanctions on countries that continue to trade with Tehran.

It's a new campaign of maximum economic pressure, as the administration tries to avoid returning to war, while struggling to break Iran's grip on the Strait of .

Nick Schifrin has more.

NICK SCHIFRIN: In the Strait of Hormuz, with vessels mostly at a standstill and diplomacy in a standoff, today, the Trump administration returned to economic pressure.

SCOTT BESSENT, U.S.

Treasury Secretary: Economic engagement of any kind with this murderous regime will expose those responsible to the full reach of American power.

NICK SCHIFRIN: Those engagements include direct flights and financial ties, but mostly Iran's revenue is from oil.

And 90 percent of Iran's crude exports are bought by China.

President Trump has emphasized U.S.-China strategic stability.

Today, Bessent neither ruled in nor ruled out new Chinese sanctions.

SCOTT BESSENT: No one is above the reach of U.S.

sanctions.

NICK SCHIFRIN: Today, Iran's currency dropped to a record low, and Iranians are struggling from massive inflation.

But Iranian leaders today threatened to block all the U.S.'

Gulf allies' oil exports, and they vowed military revenge.

MOHSEN REZAEI: We will retaliate in a seismic manner.

NICK SCHIFRIN: Meanwhile, today, there are some efforts to restart diplomacy.

Today, Pakistan's powerful army chief, General Asim Munir, visited Tehran.

He has played a key mediator role, as has Oman, whose foreign -- whose foreign minister will visit Iran tomorrow.

For perspective on all this, we turn to Miad Maleki.

He was born and raised in Iran, and, until last year, he was associate director for sanctions targeting in the U.S.

Treasury Department with a focus on Iran.

He's now a senior fellow at the Foundation for the Defense of Democracies.

Miad Maleki, thanks very much.

Welcome back to the "News Hour."

MIAD MALEKI, The Foundation for Defense of Democracies: Thanks for having me.

NICK SCHIFRIN: The U.S.

has had sanctions on Iran for years.

Why might today, why might this different version, new version of maximum pressure produce any different results?

MIAD MALEKI: That's a great question.

I mean, it's accurate to say that Iran's economy or Iran has been subject to the most comprehensive sanctions in the history of sanctions, since President Obama, when you had a secondary sanctions that was put in place, all the way until today, layers and layers of sanctions.

All sectors of Iran's economy are subject to sanctions.

What's different today, what I sensed today from Secretary Bessent's announcement is really focusing on the engagement aspects of enforcement of sanctions, meaning engagements with partisan allies and others on how we can bring these nations to enforce these existing sanctions more forcefully.

And that includes not just U.S.

economic sanctions, but you also have European Union sanctions against Iran.

You have U.K.

sanctions and many countries that have their own bilateral or unilateral sanctions against Iran.

NICK SCHIFRIN: Is what you're saying basically that the effectiveness of what was announced today dependent on diplomacy, dependent on the president diplomatically engaging with some of these countries, that still do business with Iran, whether from China, which we will get to in a second, or United Arab Emirates?

MIAD MALEKI: Absolutely.

I think sometimes a threat can be more impactful than a tool itself.

And I think what's been happening here is some engagement campaigns.

I can imagine, in the Treasury Department, their country programs or research that have been done for each country jurisdiction that still conduct trade and business with Iran.

And they have some engagement strategy, whether through direct engagements or, in some cases, rolling out sanctions actions and then engage those governments or jurisdictions to enforce sanctions better.

NICK SCHIFRIN: When it comes to the UAE, how important is it that that country, which has given Iran an economic lifeline for many years, follow through on not only the threats today, but what they promised last week, which was to cut off trade with Iran?

MIAD MALEKI: Well, that's the key on the announcement from UAE's Ministry of Foreign Affairs.

So if you look at where the naval blockade, the U.S.

naval blockade lines are, it's really outside as the Strait of Hormuz.

So what remained within the Persian Gulf was a trade and commerce between UAE and Iran.

It's really an economic lifeline for Iran to get gasoline, to get goods and services and access to the financial sector in UAE and, most importantly, the exchange houses that Iran really uses to get U.S.

dollars and also get access to the revenue from oil from China, some of which are moved to UAE.

So, now, with UAE'S decision, you can imagine how these naval blockades, a line of naval blockade are now extended within the Persian Gulf.

Now, the announcement by UAE's leadership alone can really lead to some derisking in UAE's exchange market.

Even if they're not -- there's no meaningful enforcement, that message itself can probably deter a significant level of exchange activities that Iran does in UAE.

NICK SCHIFRIN: When it comes to Iranian revenue, though, as I pointed out in the piece, it is China, right?

Ninety percent of Iranian oil exports go to China.

Explain how the sanctions announced today are supposed to help stop Beijing from that.

But, crucially, do we have any indication that President Trump is willing to sanction China?

MIAD MALEKI: Well, that's a big question.

i think, at the end of the press conference, that Secretary Bessent had a question, was, what are you doing as far as banks?

And he said, well, we will have one bank by the end of the week.

And he also said he doesn't want to blow up the financial economy or financial sector.

I take that as Treasury Department is not there yet to go after a major bank.

NICK SCHIFRIN: And especially a bank in China?

MIAD MALEKI: Absolutely.

I mean, Chinese banks are larger than U.S.

banks.

I mean, these are a major backbone of the trade between China and the U.S.

and global economy, and 80 percent of that trade goes through U.S.

dollars.

So, what happens here is, you have about 500,000 barrels of oil a day that the Chinese are purchasing from Iranians?

That's a major drop.

NICK SCHIFRIN: Despite sanctions.

MIAD MALEKI: Despite sanctions.

That's a major drop from 1.5 million barrels to 500,000 barrels a day.

So they're complying with sanctions.

So there's some level of fear of the sanctions already in China.

I think what Secretary Bessent is hinting at, engagement with these banks to make sure that the revenue from Iran's oil to China, they stay in China and they're not leaked out of these banks to the Iranian regime.

NICK SCHIFRIN: You and I have talking -- have been talking about maximum economic pressure on Iran for many years.

You were the author of some of the sanctions.

But, bottom line, there are experts who say this isn't going to change Iranian behavior, that Iran can take the pain of economic sanctions, even if China or the UAE cuts them off, and that will still not produce the results that the U.S.

wants.

MIAD MALEKI: Well, the Iranian regime will take the pain at the expense of the Iranian people.

That's what it do.

But the pressure is building up domestically.

Now, what I would say is, let's go back to the '80s.

I mean, I think historically you can see how the Iranian regime from the '80s on, they have only responded to pressure.

In the '80s, after eight years of Iran-Iraq War, in 1988, Ruhollah Khomeini then is the supreme leader.

After eight years of promising victory in that conflict, after facing major economic pressure, defeat on the ground or militarily, agreed to accept a cease-fire and gave up - - and the poison, the chalice of poison.

NICK SCHIFRIN: So, bottom line, you do think that this pressure will work and could get Iran to a cease-fire?

MIAD MALEKI: It depends on the level of enforcement, right?

If you see a meaningful enforcement, then we might get to a point that a regime is going to have to accept, as they have historically.

NICK SCHIFRIN: Miad Maleki, we will have to leave it there.

Thank you very much.

MIAD MALEKI: Thanks for having me.