The answer to that question isn't so clear. In response to Iran's "aggression" in going after a U.S. surveillance drone, a Pentagon press secretary told CNN "The United States has communicated to the Iranians that we will continue to conduct surveillance flights over international waters, over the Arabian Gulf, consistent with longstanding practices and our commitment to the security of the region. The reality is that we have a wide range of options, as I said before, to protect our assets and our forces in the region, and we'll do so when necessary."
The U.S. seems unwilling to back down, but has also been content to continue allowing Iran free reign in the area — not making a firm statement in this drone instance and not making a firm statement regarding their nuclear program. So perhaps Iran is playing some kinda of war games. May be they are not direct war games, but they are testing the waters to see how much a firm stance they can make against the American position and the U.S. not put their foot down.