Once again terrorists have reminded us how suddenly they can wreak havoc and devastation at a time and place of their choosing and how vulnerable free societies are. Once again they’ve sent a chilling message to targets of their hate around the world, a message that President-elect Barack Obama and his new national security advisors should receive with great concern.

Indian authorities suspect Lashkar-e-Taiba (LeT) is the organization behind the Deccan Mujahedeen, a previously unknown group claiming responsibility for the Mumbai attacks. Founded in 1991 by Hafiz Mohammed Saeed, a Pakistani cleric, LeT's goal is to achieve "independence" for Kashmir, and it’s been linked to Islamist terrorist suspects worldwide. In September, the Indian Mujahedeen, a group related to LeT, and responsible for previous terrorist attacks in India, issued a warning that it would attack Mumbai.

Other groups, however, may be involved. Al-Qaeda has launched attacks against soft targets in Egypt, Jordan, and other countries and is linked to LeT, but the hallmarks of al-Qaeda operations--suicide bombings and improvised explosive devices--were absent in Mumbai.

Indian and Western intelligence organizations will sort all this out eventually and determine who’s responsible for the Mumbai attacks. The FBI has dispatched agents who will assist Indian authorities in their investigation. Other US government agencies will do what that can to assist American victims of the attacks and their families.

Until he leaves office on January 20, George W. Bush will direct the US national security community’s assessment of Mumbai’s implications for the United States and determine Washington’s reaction to it. He and Secretary Rice will do what they can to prevent India-Pakistan tensions from reaching a flash point.

We’ve been free from attack in the US since 9/11, but reports of new terrorist threats against the US, and now the Mumbai attacks, remind us that we’re overdue. US federal authorities have warned of a possible terror plot against the New York City subway system during the holiday season. A November 27, 2008, Times Online article reported that, “Western intelligence services have been expecting an al-Qaeda spectacular terrorist attack in the crucial period between the end of President George Bush’s administration and the succession of Barack Obama.”

What Mumbai demonstrates is that all the security measures we’ve established to prevent attacks that involve hijacking aircraft or planting bombs on planes, trains, and automobiles aren’t enough. They aren’t designed to stop a handful of determined terrorists with automatic rifles and hand grenades from seizing hotels, churches, or similar soft targets and massacring people indiscriminately. Deranged people with guns in America do it on a regular basis. Terrorists train to do it on a larger scale.

For Obama, it’s not the pre-attack deficiencies and blame the mandatory post-attack commission will assess that need concern him at the moment. It’s how he and his administration react when we're attacked. Obama didn’t make many mistakes in his campaign for the presidency, and he’s been widely praised for people he’s selecting for key positions in his new administration. In view of Mumbai, he was wise to ask Secretary of Defense Robert Gates to stay on. Keeping Gates in charge at DoD reduces the personnel turbulence and chaos associated with transitions and maintains the pressure on our terrorist enemies abroad.

Most Americans voted for Obama to deal with the global financial crisis and the slowing US economy. So far, he’s off to a good start and should hit the ground running. Many on the left voted for Obama to end the war in Iraq and repudiate Bush's counterterrorism policies. So far it doesn't appear that Obama intends to alter the Bush/Gates/Petraeus Iraq withdrawal plan. Nor does it appear he will significantly alter the Bush counterterrorism strategy. The statement he issued following the Mumbai attacks included the sentence, "The United States must continue to strengthen our partnerships with India and nations around the world to root out and destroy terrorist networks." Obama may have already gotten the message before the Mumbai attacks.

The good news, to the extent there is any, is al-Qaeda’s ability to strike the US has been seriously degraded. US and coalition forces have decimated al-Qaeda in Iraq. The recently revealed US secret weapon--using taggant technology (small microchip devices) to identify terrorist targets in the tribal regions of Pakistan and elsewhere--has resulted in the US killing numerous al-Qaeda leaders. Experts believe Osama bin Laden, if he’s still alive, is principally concerned with his own safety and hasn’t had a lot of time to plan a new attack on the United States.

The bad news is major terrorist attacks in the United States and Europe have an uncanny habit of happening shortly before or after national elections. Both attacks on the World Trade Center in New York came in the first year of a new US president’s administration. The March 11, 2004, Madrid train bombings came just before Spain’s general elections. What better time to strike the US again, especially when our economy is teetering on the edge of a depression? Al-Qaeda may be down, but they’re not out. They don’t need Osama bin Laden or his top lieutenants to plan and launch Mumbai-style attacks. Independent sleeper cells acting on their own can do that.

Obama plans to announce his selections for his top foreign policy and national security posts this week. In addition to Gates at Defense, they’ll include Hillary Clinton for State and retired Marine Corps General James Jones, Jr. as national security advisor. Their selection may prove far more important than those he has selected for his economic team. Like Franklin D. Roosevelt after Pearl Harbor, John F. Kennedy during the Cuban Missile Crisis, Lyndon Johnson during the Vietnam War, and George W. Bush after 9/11, Barack Obama’s presidency likely will be defined by his actions and leadership as commander-in-chief, not by how he manages the economy.