President Trump has tweeted his support for protesters in Iran. But what could the U.S. realistically do to help? NPR's Robert Siegel talks with Gary Sick of Columbia University about U.S. policy options on Iran.

ROBERT SIEGEL, HOST:

President Trump and Vice President Mike Pence have tweeted out their support of Iranian protesters. This morning the president said - and this is a quote - "the people of Iran are finally acting against the brutal and corrupt Iranian regime." And he then criticized President Obama's stance on Iran. He ended his tweet by saying the U.S. is watching.

But what can the U.S. do? And what are the risks and benefits of even speaking out about Iran? Well, for that, we turn to someone with the long view, Gary Sick of Columbia University. He worked in the White House during the Carter administration and negotiated the agreement that ended the hostage crisis. Gary Sick, welcome to the program once again.

GARY SICK: It's a pleasure to be back with you, Robert.

SIEGEL: Unlike the days when you were in the White House, the U.S. now has no formal diplomatic relations with Iran. How well do we understand what goes on there and what the government is thinking?

SICK: I think the people in the government for the most part know pretty much what you and I know. It's very, very difficult to get information except through social media and all of the news sources and the like which are available to you and me just as they are to the government.

SIEGEL: President Trump is cheering on the protesters and saying the U.S. is watching. Should we take that to mean that the administration might act? Might the demonstrators take that to mean that the administration might act?

SICK: Well, when you say act, it's a little difficult to say what that would be. We're certainly not going to send troops to Iran to back a faction or something else. At this moment, it's not even clear exactly who's doing this and what their objectives are other than the fact that they started out with an economic objective, and now they seem to have moved more onto the political side. But there still doesn't appear to be any unified leadership or direction or ideology.

It's worth remembering that Iran has a very rebellious population. By some counts, Iran has had six either revolutions or sudden changes of government in just a little over a century. The fact that Iranians are out marching and protesting is not something new. But it is something that the government should be truly concerned about because they mean it. When the Iranians say they are unhappy with their government, they have a long history of actually doing something about it and even having a revolution.

SIEGEL: Considering how anti-American the Iranian government is, is there anything that the United States could say that would make relations with Iran any worse or any more problematic?

SICK: Right now, the statements that are being made in Washington are really designed for their own base. It is posturing for political purposes. Put yourself in the position of a 23-year-old worker who is out in Shiraz. And he is getting up in the morning and deciding, am I really going to go out and march in the streets again knowing that I might get arrested or worse? That is a decision that he makes on his own for his own reasons. And I don't think he is saying, what does President Trump want me to do today? It just doesn't work that way.

People are demonstrating for Iranian reasons. And we can cheer or not cheer. And it's going to have very little impact on what they do. The government will listen to what we say, and they will remember it. And they'll turn those words back against us later on if they want to. Or they may use it as an excuse to crack down on saying that this is all a U.S.-inspired operation. But on the street, in reality, our statements have only marginal effect.

SIEGEL: The Trump administration is contrasting the very public criticism they've made of the Iranian regime and the support they've expressed for protesters with what they say was the much, much more quiet approach of the Obama administration. What was the thinking behind the Obama administration's approach, and how quiet was it?

SICK: The thinking of the Obama administration I think was that they were keeping their options open for a negotiation with Iran over what they thought was a very significant issue. And that is keeping Iran from getting a nuclear weapon. So they were keeping their powder dry to a much greater degree than the Trump administration, which has basically written off Iran and is completely unrestricted in terms of the kind of statements that they make.

SIEGEL: Gary Sick, senior research scholar at Columbia University's Middle East Institute, thanks for talking with us today.

SICK: Real pleasure to talk to you, Robert.

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