Former Secretary of State Condoleezza Rice said a key lesson of the Sept. 11, 2001 terrorist attacks is that the greatest threats to the U.S. can come from "failed states" that cannot control their territory.

Rice said in a speech in Columbus on Monday that the U.S. cannot afford to leave Afghanistan an "ungoverned territory" after invading it.

The Columbus Ledger-Enquirer reports (http://bit.ly/qh5Hct) that Rice discussed her relationships with Afghanistan's leaders during Monday's Jim Blanchard Leadership Forum in Columbus. She said that she had to remind herself that the U.S. government has had more than 200 years to mature and that "governance is not a natural act" in places like Afghanistan.

Rice is now a professor of political economy and political science at Stanford University, as well as a senior fellow on public policy at the Hoover Institution.