Washington Like the opening shot in billiards that sends the balls ricocheting in directions unknown, America's war on terrorism could have unintended consequences far and wide.
U.S. policy-makers are aware that as they take their best shot against terrorism, they could set in motion problems of a different sort.
The risk of bolstering Islamic radicals, perhaps giving them enough power to overthrow moderate governments in the Arab world, is among the most apparent consequences and helps explain why the Bush administration is picking its way so carefully in responding to the Sept. 11 terror attacks.
Instability in Pakistan, which has supported the hardline Taliban regime in Afghanistan but also is cooperating with the United States, is a particular danger.
A takeover by fundamentalist Islamic factions there could be calamitous, said Jim Steinberg, deputy national security adviser for President Clinton. "You'd have an armed Islamic nuclear state," he said. "That would be a very serious unintended consequence."
Secretary of State Colin Powell has expressed confidence Pakistani President Pervez Musharraf can manage the domestic consequences of helping Americans. And, he said: "I have no concerns about their nuclear programs."
The gathering U.S. military response has already sent Afghans fleeing to borders that have been sealed off by neighboring states, and food shortages are feared with the onset of winter.
There is also the risk of upheaval in former Soviet republics in central Asia, where America has friends but border disputes are heating up and extremism is taking root.
Another indirect consequence, one with a more hopeful outcome, would be the advance of peace in the Mideast. Moderate Arab states pledge cooperation in the U.S. anti-terrorism campaign but want the Bush administration do more to get Israel and the Palestinians back to the negotiating table.
Such effects, bad and good, could occur regardless of whether the U.S.-led crackdown defeats the al-Qaida terrorist network and its leader Osama bin Laden, who has been operating in Afghanistan under the cover of the Taliban.
"It's a little like a billiard table trying to figure out exactly how it might happen," Defense Secretary Donald Rumsfeld said last week. "The balls careen around for a while."
But "the end result, we would hope, would be a situation where the al-Qaida is heaved out and the people in the Taliban who think that it's good for them and good for the world to harbor terrorists ... lose, and lose seriously."
Creating instability in five former Soviet republics north of Afghanistan could be just as problematic for America, said Fiona Hill, an expert on Russia and Central Asian affairs at Brookings Institution.
The United States has not placed a priority on furthering relations with nations such as Uzbekistan and Tajikistan, yet they may be key allies in a region where other states are not always eager to side with Americans, Hill says.
"Just the fact that we lump them together as the 'stans,' which is really a kind of a disrespectful way of referring to five very complicated countries, just shows how little we've given thought to them," she says.
These quasi-democratic nations, possible staging areas for U.S. military action in Afghanistan, have extended friendship to the United States in recent years, yet are rapidly becoming a base for extremism and terrorism, Hill says.
Buried in this list of possible repercussions is an opportunity for Palestinians and Israelis to quell violence, says Martin Indyk, former U.S. ambassador to Israel.
"There's a danger the Palestinian cause could face disaster if the Palestinians come to be identified with the terrorists and those who harbor them," Indyk said, "rather than with the United States and the international coalition against terror."