International forces under the banner of the North Atlantic Treaty
Organization are continuing to fight Taliban insurgents in Afghanistan.
But NATO field commanders are hindered by certain restrictions
placed on troops by European governments.
NATO has more than 60,000 troops in Afghanistan as part of a United Nations mandated contingent known as the "International Security Assistance Force" - or ISAF.
ISAF troops are located in most parts of the country. One of their most difficult missions is to fight insurgents in southern Afghanistan - home of the Taliban, ousted from power by a U.S.-led coalition in 2001.
Analysts say NATO is hindered in its fight against the Taliban by so-called "caveats" - restrictions placed by various NATO countries on what their forces can or cannot do.
Tomas Valasek, at the London-based Center for European Reform, describes some of those restrictions.
"What's happening is that whenever a call for troops comes in for a particular operation, the different contingents come back, or get back to the NATO commanders saying, well we'd love to take part but under the national 'caveat' we are not allowed to operate in this particular area, or we're not allowed to operate this far away from the base, or we are not allowed to operate at night," he said.
Valasek says NATO commanders in the field are finding it difficult to put together a workable strategy.
"If you are a military commander, and if you are looking at putting together a fighting force out of what is already a hodge-podge of national militaries, and you're finding that each one operates under a different set of rules - some of them very restrictive - well, that's a very difficult way to fight a war. Caveats have been a tremendous frustration to the NATO commanders," he said.
Most of the fighting in Afghanistan is taking place in the south. But the Taliban has expanded its range of action to the east and to the relatively peaceful north.
Robert Hunter, former U.S. Ambassador to NATO, says the presence of "caveats" means only a few countries are bearing the brunt of the heavy fighting.
"The United States, Britain, the Dutch, the Canadians, who've actually had more fatalities in Afghanistan than any war since Korea - what 50, 60 years ago," he said. "The Estonians, the French are doing a bit more, the Poles do a bit. But most of the rest of the allies are not involved, really, in that most dangerous part of the country."
The United States is the largest contributor to the ISAF force with approximately 30,000 soldiers and Marines. Their presence in the most dangerous areas of Afghanistan has prompted some U.S. soldiers to say ISAF - the "International Security Assistance Force" - stands for "I Saw Americans Fighting", or "I Stop At Five", a reference to the European "caveats".
During a recent speech to the Veterans of Foreign Wars, President Barack Obama said the Taliban insurgency will not be defeated overnight.
"This will not be quick, nor easy," he said. "But we must never forget. This is not a war of choice. This is a war of necessity. Those who attacked America on 9/11  are plotting to do so again. If left unchecked, the Taliban insurgency will mean an even larger safe haven from which al-Qaida would plot to kill more Americans. So this is not only a war worth fighting. This is fundamental to the defense of our people."
Many analysts say this is the fundamental difference between Washington and many European countries: whereas the U.S. believes Afghanistan is a national security issue, the European public does not.
Charles Kupchan is with the Council on Foreign Relations in Washington D.C. "They do not believe, for example, in Germany, that German forces are protecting German territory from a potential strike by al-Qaida," he said.
"And as a result of that, it is difficult for the German government to make the case to the German public, not only that they should send more troops, but that those troops that are already there should stay and should run the risk of physical harm. And so a lot of it is that the Europeans simply have not done a good enough job of making the case to their publics for the war in Afghanistan," he added.
Some analysts are also questioning whether the Obama administration has done enough to convince the American public the U.S. must stay - at least for the time being - in Afghanistan. A recent public opinion survey indicates 51 percent of those questioned say the war in Afghanistan is not worth fighting.
"If the war in Afghanistan does not go well, then I think by sometime in 2010 Obama may have a domestic problem. And those who worry about Afghanistan becoming Obama's Vietnam may say: 'I told you so," said Kupchan.
In the meantime, experts say the U.S. must convince the Europeans to do more in Afghanistan for NATO to succeed.
They say if the Europeans have an interest in keeping NATO strong - as they say they do - then it requires doing some unpopular things - like sending troops to dangerous areas in Afghanistan.