During a gathering in Tehran, a woman holds a picture of newlyweds, victims of the crash of Ukraine International Airlines Flight 752.Nazanin Tabatabaee / WANA via Reuters

Last weekend, Donald Trump offered Iran some sage, if obvious, advice: Do not kill your protesters.

The warning came amid ongoing demonstrations in Iran following the country’s admission that it had mistakenly struck down a Ukrainian airliner, killing all 176 people on board, including 83 Iranian nationals. The announcement followed days of denial and obfuscation by Iranian authorities. Anger about the government’s apparent misleading of the public has resulted in the outpouring of thousands onto the streets, some of whom are calling on the country’s supreme leader, Ayatollah Ali Khamenei, to resign.

Iran is known to be particularly heavy-handed when it comes to cracking down on protests—something President Trump appeared to be referencing when he urged the Iranian government against “killing … your great Iranian people!” Last month’s demonstrations over rising fuel costs led to the deaths of as many as 208 people at the hands of Iranian security forces. Similar unrest in 2009, following a disputed presidential election, resulted in at least 72 deaths.

Most foreign leaders call for maximum restraint and calm when such violence occurs, if indeed they choose to say anything at all. But Trump is no ordinary foreign leader, nor was his warning to the Iranian government—which was uncharacteristically written in English and Persian—an ordinary appeal. His advocacy lays bare the challenges foreign countries face when weighing in on protests that are not their own, such as how to support demonstrations without undermining them or how to raise the profile of protesters’ demands without unwittingly compromising them.

The protests currently taking place in Iran are not unlike mass movements around the world—many of which have been subject to violent government crackdowns. This violence has largely backfired: In their attempts to quash these protests, the authorities have paradoxically mobilized more people to join them, making the protesters’ cause—and their demands—impossible to ignore. The violent response has also invited the sympathy and support of foreign governments. In the United States and Britain, for example, lawmakers have expressed solidarity with protesters in Hong Kong, where demonstrations against a narrowly focused extradition bill have evolved into a months-long prodemocracy movement.

Though such foreign overtures have a way of propelling these movements, they can also be used to undermine them. In response to the United States’ unanimous passage of a bill supporting Hong Kong’s prodemocracy activists, Beijing harangued Washington for intervening in its internal affairs—an accusation fitting with China’s overall effort to portray the unrest in Hong Kong as a product of “Western interference.” The country has charged Britain with doing the same.

Efforts to undermine protest movements by framing them within a narrative of foreign or oppositional interference are part of a familiar autocratic playbook. In India, Prime Minister Narendra Modi dismissed ongoing protests against the country's new citizenship bill as being propagated by his political opponents, whom he blames for “spreading violence and creating an environment of fear.” Anti-Putin demonstrations in Russia ahead of local elections in Moscow last year were similarly attributed to “foreign meddling.”

In some countries, protesters have come to expect this sort of delegitimization—and have even taken steps to avert it. In the recent anti-government protests in Iraq, for example, demonstrators intentionally framed their movement as nonsectarian in an effort to avoid delegitimization by the state. “There are particular reasons why the Sunnis in Iraq are not out on the streets in large numbers,” Lina Khatib, the head of the Middle East and North Africa Program at the London-based think tank Chatham House, told me in October. Iraq is a Shiite-majority country, and Khatib noted that the distinct lack of Sunni protesters had to do in part with the fear that mass mobilization in Sunni areas would lead to “people accusing these Sunnis of rising up against the government because they are pro-ISIS,” and make the protests easier for government forces to stamp out.

Trump’s apparent endorsement of the protesters in Iran puts them in a similar bind. While his pledge to stand by them raises the international profile of their cause (certainly compared to last month’s anti-government demonstrations), it comes with the price of being tied to Trump himself: a figure the Iranian government can easily point to as a hostile, and therefore delegitimizing, force. Iranian President Hassan Rouhani has already attributed last year’s protests about rising fuel costs to “subversive elements” backed by the U.S., Israel, and Saudi Arabia. The intensification of hostilities following the U.S. killing of Iranian general Qassem Soleimani this year is likely to strengthen such arguments.

Trump’s warning also has only as much weight as the Iranian government is willing to give it—and the U.S. doesn’t exactly have a proven track record of following up its warnings with action. Anticipated American support for the 1991 uprising against Saddam Hussein in Iraq (which was endorsed by President George H. W. Bush) never materialized. President Barack Obama’s “red line” on Syrian President Bashar al-Assad’s use of chemical weapons ultimately proved an empty threat.

This isn’t to say that foreign leaders should turn a blind eye to worldwide protests. Indeed, their response plays a role in reminding governments that the treatment of their citizens—even within their own borders—is not immune to international scrutiny. But that doesn’t exempt leaders from thinking about how vocalizing their support aids protest movements in other countries, if it does at all. Part of this means interrogating what support for civil society elsewhere actually looks like. Tweets can’t shield protesters from heavy-handed crackdowns. Expressing support for the “great Iranian people” might bring more attention to their cause but, as some observers note, so too could more policy-driven options, such as reversing the U.S. travel ban currently imposed on them or lifting the crippling economic sanctions against them.

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