WASHINGTON  For two days this month, Gen. James L. Jones, President Obama’s national security adviser, and Manouchehr Mottaki, the Iranian foreign minister, were in the same place at the same time, attending a high-level security conference in Munich with a number of high-ranking officials from around the world. And yet the two made no plans to meet with each other.

Whatever happened to engagement?

As a presidential candidate, Mr. Obama declared himself open to dialogue even with intransigent states like Iran. But there is little diplomatic nicety to be seen these days, as the administration presses tough new sanctions aimed at the Islamic Revolutionary Guards Corps in Iran, and Secretary of State Hillary Rodham Clinton warned Monday of a drift toward a military dictatorship.

White House officials maintain that they have not abandoned Mr. Obama’s pledge of engagement, and point to the numerous times in the past year that he reached out to Iran, including a YouTube video to the Iranian people; a letter from Mr. Obama to Iran’s supreme leader, Ayatollah Ali Khamenei; and even an offer to help Iran buy isotopes for a medical research reactor.

But the nonencounter in Munich between General Jones and Mr. Mottaki, like the full court press on Iran by Mrs. Clinton and other envoys to the region this week, shows that the administration is coming to terms with the limits of its engagement policy, many foreign policy experts say.