Peter Scoblic sat in on Clinton's address yesterday:
The key idea of the speech was that, because no nation can meet modern threats like proliferation and climate change on their own and because most nations worry about those threats, the United States should establish an "architecture of global cooperation." [...] Clinton made clear that she was looking for something beyond containment, unilateralism, or balance-of-power realism. What's more, the administration is clearly not relaxing its emphasis on engagement with rogue regimes despite criticism over its handling of Iran's elections, because "[a]s long as engagement might advance our interests and our values, it is unwise to take it off the table."
Finally, Clinton emphasized the essentiality of American leadership to global cooperation--"just as no nation can meet these challenges alone, no challenge can be met without America"--which I think is important both because it's true and because it represents a constructive interpretation of American exceptionalism that can be leveraged to our benefit.