Leaders of nato's 26 member states gather this week in the Latvian capital, Riga, for a summit that will trumpet the solidarity of the world's most successful military alliance. The scripts have been largely written and surprises are unlikely. But as Christoph Bertram, the dean of German security experts, recently noted, the affair will be "like a Christmas service for agnostics, who for most of the year do not pray together or sing from the same hymnbook." The question of what the North Atlantic Treaty Organization should do and become has been a subject of often deep disagreement since the Warsaw Pact dissolved in 1991. Here's a snapshot of where the alliance stands today.

How tough is its fight in Afghanistan? Tougher than most thought it would be when nato first deployed forces in August 2003 to help the nascent Afghan government maintain security. "If we fail in Afghanistan it could be the end of the alliance," says Ronald D. Asmus, director of the Transatlantic Center of the German Marshall Fund of the United States, a security think tank in Brussels. "It would be like losing the Korean War at the beginning of the cold war." There's not a single nato member state who would argue otherwise, yet the trend line is not encouraging. This year has been the deadliest since the fall of the Taliban in 2001: insurgent and terrorist attacks have killed some 3,700 people since January, including at least 143 international troops. The insecurity is reversing economic gains as foreign aid workers withdraw from dangerous areas. What nato once considered a stabilization mission has become a war-fighting one.

Are the 31,000 troops in Afghanistan enough? More troops could be put to good use: nato has 16,000 soldiers in Kosovo, which is less than 2% the size of Afghanistan. But with major contributing countries already stretched in Iraq, Kosovo and Lebanon, a big infusion of new soldiers is not realistic. So the Riga horse-trading will concentrate on a related problem: that commanders often can't deploy existing troops as they would like because of national limits — or "caveats" — on their use. U.S., British, Canadian and Dutch troops are doing most of the frontline fighting; support from many of the other 33 countries in the nato-led International Security Assistance Force (isaf) ranges from secondary to symbolic. At Tuesday night's dinner with other nato leaders, U.S. President George W. Bush is likely to take up the demands of isaf commander General David Richards that national governments loosen the strings. He will get support from Polish Defense Minister Radek Sikorski, who told Time: "What is the use of having the troops there if you can't use them when they are needed?"

Will that appeal work? Not yet. Germany, the third biggest troop contributor to isaf, has been the focus of the caveat debate because its 2,900 troops are restricted to the more secure regions of Kabul and the north. Karsten Voigt, coordinator for U.S.-German relations in the Foreign Ministry, says he is under constant pressure to do more in Afghanistan: in Washington last month, he says, one interlocutor told him that "Germans have to learn how to kill." Berlin will not budge, though, since neither the government nor the public has the stomach for putting German soldiers in harm's way. Mindful of that political reality, Bush isn't likely to push for a sea change. Nevertheless, it was only seven years ago, in Kosovo, that Germany first committed combat troops to a nato mission at all. Over time, if Germany moves into a foreign-policy role consonant with its economic weight, a more self-assured stance might become politically acceptable.

Is nato fighting the right way in Afghanistan? Many are beginning to wonder. nato says its two-week offense in September, Operation Medusa, drove insurgents out of the Taliban strongholds of Panjwai and Zhari districts in Kandahar province. Daan Everts, nato's senior civilian representative in Afghanistan, calls it a "critical turning point." But that operation also killed at least a dozen civilians. "If nato cannot bring our people security and a peaceful life, then it has failed," says Noorolhaq Olomi, an M.P. from Kandahar and chairman of the parliament's defense committee. "There is no reconstruction, just destruction." Despite efforts to help reconstruction work around the country, a military force like nato doesn't have the resources or expertise to make Afghanistan's huge deficits — poverty, pervasive corruption, poor education, a thriving drug trade — quickly disappear. Yet no one else is providing such help at the scale required.

Would ad hoc military alliances work better than nato? nato has been a rather unloved son in recent years. "We've had an unholy coalition of American and French unilateralists undercutting nato for different reasons," says Asmus. Outgoing U.S. Defense Secretary Donald Rumsfeld — who won't be in Riga — didn't want to be forced to forge unanimity around a table, so he ignored the alliance, even after it speedily invoked its "common defense" clause, for the first time in its history, after the Sept. 11 attacks against the U.S. France, for its part, will always see nato as a U.S. appendage. And while Paris is willing to commit troops to dangerous places, as it's doing now in Afghanistan, Kosovo and Lebanon, its officials are a long way from embracing nato. But no one is ready to dump the alliance. Its permanent structures, however unwieldy, are still the best way to muster, coordinate and confer legitimacy on international troops.

What's nato's brief? "Our agenda with Europe is now a global agenda, and it tends to be about the rest of the world, about what we can do as partners in the Middle East, in South and East Asia, in Africa and in Latin America," said U.S. Under Secretary of State R. Nicholas Burns last week. Washington wants to enhance the alliance's relations with like-minded allies such as Japan, South Korea and Australia, arguing that the West is as much an idea as a geographical concept. But don't expect to see that idea reflected in the final Riga communiqué: a global nato makes many allies, most notably France, uneasy. "We think there are enough problems with nato in Afghanistan and Kosovo; we don't need to get involved in the Taiwan Strait," says a French Defense Ministry official. Many European governments, France in particular, worry that "expanding nato into an alliance of democracies [could be] interpreted as 'the West against the rest,'" says Daniel Keohane, a security expert at the Centre for European Reform in London. The summit will endorse a mechanism for coordinating with out-of-area allies, but not the formal ties Washington has been hoping for.

Do nato and the E.U. Know what each other is supposed to do? Not entirely, but the subject isn't nearly as fraught as it was five years ago, when an assertive European Union seemed on track to create military command structures that would compete with nato's. While the E.U. is now independently running military operations in Bosnia, Macedonia and Congo and doing delicate work in East Timor and Gaza, that's no longer neuralgic for nato. "Frankly, we want more nato and more E.U.," says a senior U.S. official. But the idea of a robust E.U. military arm stumbles on the lack of an E.U. constitution, and falls on the matter of defense budgets: only six of nato's 24 European members meet its benchmark of spending 2% of gnp on defense, and U.S. spending, at 3.7%, far eclipses the European average. Europe can dream of independence from U.S. security, but to make it happen, its governments have to spend more. And they have to face the reality that even the most humane diplomacy sometimes has to be backed by military force.

• JAMES GRAFF | Brussels
• Difficulties in Afghanistan make questions about NATO's post-cold war role more urgent than ever