Members of the 9/11 commission in Washington are dominating headlines as they investigate what the government did before that dark day to prevent terrorism. But the terrorists aren't interested in looking back. They're looking forward -- to their next attack.

Today, we face a different terrorist threat far different from that of two and a half years ago. After 9/11, the Bush administration aggressively dismantled bin Laden's network, destroyed his operations base in Afghanistan, killed and captured senior leaders, and disrupted al Qaeda operations worldwide.

But war isn't conducted on inanimate objects. War is a competition between two determined enemies. Al Qaeda operatives have responded by trying to rebuild their operational assets, focusing on recruiting and fundraising. They also have incited regional groups to attack on their behalf and spur support for their causes.

Their latest strategy is to exploit disaffected groups already in place. As a result, the United States and its allies may well see an upsurge in terrorist strikes that don't require visas, shipping containers or international travelers. The terrorists may already be here.

While the events of 9/11 focused American attention on foreign foes, concern over domestic groups that perpetrate violence can't be ignored. Before the attacks, the most deadly strike on U.S. soil was the bombing of the Murrah Federal Office Building in Oklahoma City -- an act carried out, we should remember, by domestic extremists.

Many groups could provide the foundation for the next wave of terrorism. By some counts more than 600 organizations, with memberships ranging from a handful to hundreds, have shown the willingness and capability to launch deadly attacks.

True, these groups represent lesser dangers than groups such as al Qaeda. However, domestic groups that act in sympathy or as offshoots of transnational networks could represent serious security risks.

The threat of domestic terrorism has waxed and waned in the United States over the years. In the 1980s domestic terrorist activity declined significantly and the nature of those perpetrating it shifted from predominantly left-wing extremists tied to the anti-Vietnam War movement and civil-rights protests to right-wing organizations espousing racial supremacy and anti-government ideology.

By the mid-1990s, acts of domestic terrorism had leveled off. But in the last several years, violence from groups associated with animal rights, anti-globalization, and environmental extremism has been rising. For example, the FBI estimates that since 1996, the Earth Liberation Front, an ecological terrorist group, has committed hundreds of criminal acts costing more than $42 million.

It's not clear what effect al Qaeda's latest incarnation may have on future trends. The greatest danger is concerted operations by multiple actors -- domestic groups, individuals and transnational outfits acting together. This cooperation might occur not out of shared motivations or planning, but rather out of a common desire to wreak violence and destruction. But it's possible that international and domestic groups might work closely together, driven by ideology or financial gain.

What can we do? Frustrating what some experts call "al Qaeda 2.0" is a good start. We need to continue to have instruments such as the Patriot Act, which allow effective teamwork between intelligence and law enforcement, while protecting the civil liberties and privacy rights of our citizens. Meanwhile, we must continue to expand cooperation and information-sharing between local, state and federal agencies.

We also need to preserve our domestic law enforcement institutions the way they are. Creating a separate federal intelligence arm, for example, is a bad idea. FBI intelligence efforts are bound by judicial oversight and investigatory rules put down the Justice Department. It works well that way. Let's not tie the FBI's hands; let's just make sure it has the resources it needs to be effective.

In the end, our leaders can't stop every terrorist attack. Some future Timothy McVeigh will get through sooner or later. Local, state, and federal officials can, however, work together to penetrate conspiracies, disrupt operations and dismantle terrorist networks and their supporting infrastructure -- while preserving a free and open civil society. It's the only way to ensure we never see "al Qaeda 3.0."