The Islamist terrorist attack on Mumbai sets the stage for another major war between India and Pakistan. To avoid it, statesmen will have to control inflamed public passion and manipulative politicians as well as confront the terrorists responsible for the heinous crime.

Diplomats know the act of mass murder spurs legitimate anger and rage. Mumbai's death toll reached 180 earlier this week, with some 240 people wounded. Most of the dead were Indians, but the list of victims included foreigners from at least 12 other countries, including the United States, Germany, China, Great Britain and Israel.

India's outrage has deep roots. Islamist terrorists likely connected to Pakistan have struck Mumbai many times, with attacks in 1993 and 2006 particularly notable. The July 2006 attack mimicked al-Qaida's March 2004 bombing of commuter trains in Madrid. 2008's massacre-by-gunfire tactically and strategically echoes the December 2001 assault by Islamist gunmen on India's parliament building in New Delhi. That attack killed 12 and chilled prospects for a 9-11-inspired India-Pakistan rapprochement based on combating terrorism.

With anger seizing India and fear of Indian attack gripping Pakistan, rhetorical belligerency is inevitable. Indian and Pakistani media reflect this war of words. Both governments have redeployed military forces, with the contested state of Kashmir the focus.

Mediating anger and fear requires intricate diplomatic judo. Rhetoric is fine, as long as it releases passion rather than feeds it. To paraphrase Winston Churchill, "jaw jaw" is preferable to "war war." Diplomatically structured troop movements are also permitted, where Indian and Pakistani commanders know the other side's moves. This dangerous theater buys time for cool-headed leaders pushed by politicians demanding war. "Quartet discussions" involving India, Pakistan, the United States and the U.N. Security Council are a diplomatic venue for directing this theater. U.S. satellite and electronic intelligence assets are good at tracking large-scale conventional troop movements and provide a trust-building "third-party eye."

The diplomats' goal is to avoid the strategic catastrophe of an Indo-Pakistani war -- thwarting what I believe was the terrorists' strategic aim.

The Pakistani government says it wants to "dampen down the discourse of conflict and work toward regional peace." Good. Ensuring peace between India and Pakistan ultimately requires defeating the terrorists, and that entails effective, coordinated action.

India wants Pakistan to arrest and then extradite several terrorists, including Dawood Ibrahim. The Indian government believes Ibrahim orchestrated Mumbai's 1993 terror bombing. Pakistan needs to comply. India also wants action against terrorist bases. Indian media report that the terrorist captured in Mumbai, Ajmal Qasab, claims he trained at camps in Pakistan run by the Islamist and Kashmiri organization Lashkar-e-Taiba (LET). Though LET spokesmen deny it, Indian intelligence believes LET is responsible for the Mumbai assault and was behind the 2001 parliament attack.

LET is an al-Qaida ally. While al-Qaida serves as a global ideological collective for assorted Islamist sociopaths who use terror to achieve their own local or regional political goals, its connections with LET are long-term. According to the State Department, in March 2002 Pakistani security arrested al-Qaida "operations planner" Abu Zubaydah in a safehouse operated by LET. Personal connections go back to the mujahadeen war against Russia in Afghanistan -- that battle zone on the other side of Pakistan. They also connect through Pakistan's fragmented, corrupt, yet still potent Inter-Services Intelligence directorate (ISI). LET and rogue ISI operatives are dangerous to Pakistan, and Pakistan needs to shut them down.

Al-Qaida lost in Iraq. It has now shifted its main effort to Afghanistan and Pakistan. Despite the negative headlines, al-Qaida is losing in Central Asia. As StrategyPage.com noted on Nov. 20, al-Qaida's tactics aren't working in Afghanistan because there is "popular opposition to Islamic terrorism" and that Pakistan's "army offensive against the Taliban in Pakistan" has hurt the terrorists. For the last six months, strikes on al-Qaida and Taliban sanctuaries in Pakistan have been increasingly effective.

The terrorists' gambit? Replay December 2001 for bigger stakes. A mass slaughter in Mumbai ignites a war with India and moves the Pakistani Army from the Afghan border.