Iranians demanding both social and economic reform in their country have taken to the streets again. This time, U.S. leaders should not let them down.

Massive demonstrations in Tehran and many other cities have been in progress for several days. In some ways, they appear to be a repeat of what happened in 2009, when millions of Iranians demanded reform.

Then-President Barack Obama made it perfectly clear his sympathies were not with the demonstrators. There would be no support for them from Washington, he indicated.

At that, Iran’s repressive regime came down hard and violently on the demonstrators. The reform movement was crushed.

Obama’s failure has been criticized by his successor, President Donald Trump. But will the new U.S. leader do anything to support the protesters?

He should. Trump’s options are limited for the most part to economic sanctions and use of the bully pulpit to voice support for the reformers.

Obama would not do even that, however.

Trump should make it plain that repression in Iran is not acceptable — and that Americans support those who seek freedom in that country. We should not let them down again.