The presidential candidates have discussed quite a few issues in this campaign. Strangely, though, voters have heard little about homeland security.

Yet the risks to America's hometowns are as high as they've ever been, if not higher. The terrorists are still out to get us. Al Qaeda has reconstituted itself in the border regions of Pakistan and Afghanistan, and redoubled its effort to inspire "self-radicalization" worldwide. We see glimpses of its recent success with new or thwarted attacks in Germany, Britain, Turkey, Saudi Arabia, and yes, even in the United States, where authorities foiled attempts last year to blow up the JFK Airport fuel line, and to attack the military base in Fort Dix, N.J.

Nor have natural disasters diminished. Indeed, the number of declared disasters rises every year. There's no telling what might happen on the next president's watch. Will California experience the "big" earthquake? Will a Category 5 storm hit Manhattan? Will some virus change its genetic makeup and become a global killer?

As Hurricane Gustav headed for shore, John McCain and Barack Obama emphasized the importance of presidential leadership. Unfortunately, those sound bites and photo ops told us little of what they might actually do as president. We need to know.

Is a post-Katrina FEMA on the right track? Should we welcome foreign visitors or place tighter controls at the border to protect America from terrorist threats? Should we build border fences or invest in tougher immigration enforcement? Should government regulate private-sector security to ensure critical infrastructure is protected, or encourage voluntary public-private partnerships? How should we fund continued investments and operational costs of our local first responders?

The list goes on. The Patriot Act, for example, is up for renewal next year -- should it be reauthorized? Foreign ownership of critical infrastructure will continue to be a question: After the Dubai Ports debacle, politicians aligned against foreign ownership, despite the fact that it could have enhanced our security. Now airlines plagued with financial problems are looking for foreign investment to stay afloat -- where does the next president stand on this? And should we scan all cargo coming into America for radiological or nuclear bombs?

Too often, discussions on homeland security end up singling out the Department of Homeland Security as the problem, the challenge and the solution. The next administration must recognize, however, that the department is only one part of a much larger homeland security system -- or it should be. The most urgent task is not to move about pieces in the department, but to establish a truly national homeland security enterprise that integrates all elements of society to protect America against catastrophic events.

Although the Department of Homeland Security's budget accounts for about half of all federal domestic security expenditures, the homeland security budgets of the Departments of Defense, Health and Human Services, Justice, Energy and State are also significant. And virtually every agency has some responsibility for homeland security.

The real strength and the front lines of prevention, protection, response and recovery, though, are at the state and local levels. They're with the emergency responders and the firms that operate private infrastructure, as well as with families and communities and their ability to handle disasters.

The terrorist threat is nimble and dynamic. It exploits the seams of our society, operating in the gaps between bureaucratic notions of foreign and domestic, state and federal, civil and military, public and private. We must weave a national homeland security enterprise as agile and seamless as those who seek to harm us.

Voters need to know what the candidates propose to build such an enterprise -- one that not only thwarts terrorists, but respects constitutional liberties and promotes economic competitiveness. Here are several recommendations McCain and Obama would do well to embrace:

1. Foster a culture of preparedness by focusing on making communities and individuals more self-reliant and less dependent on Washington.
2. Shift from a strategy that tries to "child-proof" critical infrastructure to one that builds and sustains an infrastructure that can take a hit and keep going.
3. Expand international cooperation, since real homeland security begins far from home.
4. Develop a clear framework for domestic intelligence, one that safeguards liberty and defeats terrorists equally well.
5. Improve professional development in security and public safety at all levels of government -- ensuring that leaders really can lead.

As we remember those killed on Sept. 11, 2001, let's continue to do all we can to make America more secure against all threats, natural and man-made. That effort will continue with new presidential leadership in January. It's time for the candidates talk about it.

David Heyman is a senior fellow at the Center for Strategic and International Studies (csis.org). James Jay Carafano is a senior research fellow for national security at The Heritage Foundation.