“September 11 Changed Everything”

No. The massive forces of international trade and globalization were largely unaffected by the attacks of Sept. 11, 2001. China’s emergence as a new economic giant in East Asia continues, with all its economic, diplomatic, and military implications. Decades-old flash points remain. China and Taiwan still stare at each other suspiciously across the strait. The conflict between nuclear-armed India and Pakistan over Kashmir shows no signs of resolving itself. North Korea’s cycle of provocation and retreat with the United States and Japan hasn’t changed fundamentally since the Clinton administration.

Even within the Middle East, there is more continuity than change. Al Qaeda’s strike didn’t answer the questions of Iranian influence in Syria and Lebanon and of the long-term impact of Ayatollah Khomeini’s revolution on the region. The world’s reliance on oil from the Persian Gulf is as strong as ever. The sclerotic but stubborn Saudi and Egyptian regimes linger on. Israel is still battling militants in southern Lebanon and the Palestinian territories. For all their visibility and drama, the 9/11 attacks left untouched many of the underlying forces and persistent tensions that shape international politics.

“9/11 Was a Victory for Al Qaeda”

Probably. Post-9/11 terrorism—from Bali to Madrid to London—has become the province of small, local groups who are emulating al Qaeda but not in direct contact with it. These cells can learn a few tricks on the Internet, and they can certainly inflict pain, but they cannot hope to accomplish much. At most, they can carry bombs onto trains.

The economic and social...