If I were President Mahmoud Ahmadinejad of Iran, I would be feeling a little nervous after watching Obama’s speech to the U.N. General Assembly this morning.

First of all, Obama made it clear that his administration is still holding open a door of diplomacy “should Iran choose to walk through it.” But it remains incumbent on Iran to prove to the world that its nuclear intentions are peaceful.

Then he turned to human rights. Now, the Islamic Republic of Iran is already paranoid about a “velvet revolution” that could threaten its power. That explains its crackdown on the Iranian opposition since Ahmadinejad was reelected in last year’s contested elections, after which hundreds of people were imprisoned, many tortured and at least three killed.

But just because you’re paranoid doesn’t mean they’re not out to get you. Here’s what Obama had to say today: “Civil society is the conscience of our communities, and America will always extend our engagement abroad with citizens beyond the halls of government. And we will call out those who suppress ideas and serve as a voice for those who are voiceless. We will promote new tools of communication so people are empowered to connect with one another and, in repressive societies, to do so with security.”

Remember the “Twitter revolution” in Iran? Although Obama does not go so far as to name Iran in this context, his words should be comforting to the protesters who felt that America had let them down by failing to condemn the ruthlessness of the authorities.

What’s more, Obama is now urging other countries that have thrown off oppressive regimes — from South Africa to South Asia, from Eastern Europe to South America — to speak out for freedom. “Don’t stand idly by, don’t be silent, when dissidents elsewhere are imprisoned and protesters are beaten,” he said.

Obama has finally grasped the nettle of human rights to assert it loud and clear as a driver of future U.S. policy. “History is on the side of liberty,” he said today. “The strongest foundation for human progress lies in open economies, open societies and open governments.” Standing up for universal values is “the right thing to do.” And what’s more, democracy, “more than any other form of government, delivers for our citizens.”

This was a combative speech delivered to an audience where quite a few leaders may have felt targeted by the “tyrant” label he used.

Citizens of the world, unite; you have nothing to lose but your chains! Could it be that the president is a Marxist after all?