Was it our imagination, or was President Obama showing flashes of anger on Tuesday while explaining his new, tougher tone on the political upheaval in Iran?

Obama opened his fourth solo White House news conference with his strongest condemnation yet of the Tehran regime, declaring, "No iron fist is strong enough to shut off the world from bearing witness to peaceful protests of justice."

By calling out authorities for threats, beatings and imprisonments, and invoking the widely viewed scene of a young woman bleeding to death from an apparent gunshot wound, Obama departed from his detached, measured approach to the Iranian crisis -- one predicated on respecting Iranian sovereignty and not making the U.S. a convenient scapegoat for Iranian authorities.