White House Chief of Staff Rahm Emanuel sought Thursday to tamp down expectations for the effect of President Obama's speech this morning in Cairo.

"Let me try to lower the expectation that one speech is going to deliver a silver bullet that all the year of differences are going to somehow evaporated," Emanuel told ABC News. "If that's the standard, you're going to be disappointed."

Obama's speech in Cairo, in which he sought a "new beginning" with Muslims around the world, has already received top headlines for its effort to reach out to that community.

Emanuel talked up the effect of that speech on the public relations front.

"America is no longer losing that PR war," he told ABC. "If you go over the past eight years, everyone was always complaining that America was losing the PR war."

The White House chief of staff also spoke of the "moment of truth" between Israelis and Palestinians, which he said those people must seize.