Put aside your fear and loathing for a moment, because we need to discuss the business of travel terrorism. Like it or not, acts of terror aimed at travelers and the places they frequent are very good business tactics indeed.

Consider last month's seizure of the airports in Bangkok, a development understandably overshadowed by the much more violent terrorist acts in Mumbai. While the world focused on India, anti-government mobs in the Thai capital shut down both Bangkok's relatively new international airport and its older domestic facility. When the airports finally reopened over the weekend, the 10-day occupation had accomplished its goal: The prime minister was ousted, his party banned, and most of his top functionaries banished from politics.

The coup was technically accomplished via court action, but the legal verdict came only after the demonstrators began the airports blockade and a bombing killed one of the protesters. A three-month-long siege of the prime minister's office had been fruitless. In fact, halfway through the airports crisis, protesters abandoned the prime minister's office and moved in with the mobs occupying Suvarnabhumi International and Don Muang airports.

Why did a week-and-a-half-long airport shutdown effect political change when a three-month-long occupation of the putative seat of Thai political power had failed? The power of the purse. By shutting down Bangkok's airports, demonstrators essentially shut down the Thai economy.

Tourism, which accounts for as much as 12 percent of Thailand's G.D.P., ground to a halt. Depending on who was counting, between 100,000 and 300,000 travelers were stranded: In-country visitors were stuck at Thai resorts, outsiders couldn't get in and business fliers, who use Bangkok as a hub for South Asia travel, scrambled for alternatives. Mail stopped flowing and critical supplies stopped moving, hobbling other Thai businesses. Billions of dollars of imports and exports, many of them perishable goods like food and flowers, stalled in the global pipeline.

The long-term effect may be even more dramatic. Edward Carter, a former businessman and hotelier who is now a professor of hospitality at Bangkok University, thinks tourist arrivals will sink by 40 percent in the next year. "The impact on five-star vacation properties will be twice as bad," he predicts. "Bigger-ticket travelers have much greater choice" and they will opt to spend their money in countries they perceive to be less risky and less chaotic.

Chaos is what the terrorists who killed nearly 200 in Mumbai last month were hoping to cause, of course. And about half of their targets were travel-oriented: They attacked the city's main rail station and a restaurant favored by international visitors. They also struck at the iconic Taj and Oberoi hotels, the two pre-eminent names in Indian hospitality.