Writing in the Chinese newspaper Global Times a few days ago, the well-known American Sinologist David Shambaugh called on China to send its troops to fight alongside US forces in Afghanistan.

"The international community has a common mission to destroy Al Qaeda and the Taliban and bring stability and security to Afghanistan and the Pakistani border region. Yet where is China?" he demanded. "It would be much better for China's image as a responsible major power to be seen contributing (and dying) alongside NATO."

Stephanie T. Kleine-Ahlbrandt of the International Crisis Group, a think tank financed by NATO member states, followed up by accusing China of avoiding its international responsibilities and being "a global free-rider".

"While threats to international peace and security increase, China is still not stepping up. Beijing remains highly reluctant to take on more burdens – whether economic, political, or military – preferring to free-ride," she said. (In fact China contributes more peacekeeping troops to UN missions than any other permanent member of the Security Council - and elsewhere in her article Kleine-Ahlbrandt welcomes China's efforts).

Both commentators implied that demands for China to get involved in US-led military operations would figure in President Obama's discussions with Hu Jintao when he visits Beijing this week.

If so, it would simply underline the desperate plight of the US/NATO effort in Afghanistan. The Taliban insurgents daily demonstrate their ability to attack at will and, according to experts, already control more than half the country's territory. America's allies are deserting it. Japan recently announced its navy will no longer provide refueling facilities for US and NATO ships. The Netherlands has said it will withdraw its troops next year and the Canadian parliament has voted to pull out by 2011. Germany and France keep their troops in relatively peaceful areas. Only the ever-faithful British look like staying the course, in the face of overwhelmingly hostile public opinion.

Most seriously, it is entirely unclear what US objectives are in Afghanistan. What does the "mission to destroy Al Qaeda and the Taliban" amount to? Al Qaeda is primarily an idea, not an organization. It is everywhere and nowhere, and America's wars are its most effective recruiting sergeant. Meanwhile, "Taliban" is little more than a catch-all term for every rebel Pashtun who takes up arms against the occupation. The longer foreign troops stay, the stronger they become.

If any Americans still thought they were fighting for democracy, their unruly puppet, Hamid Karzai, put paid to that delusion by stealing the presidential election with the help of his brother, Ahmed Wali Karzai, who, say the US media, is both a drug lord and on the CIA payroll.

Yet, it seems that, when Obama finally gets around to making up his mind, the US answer to these essentially intractable problems, will be another "surge" in troop numbers. As the American philosopher George Santayana said "a fanatic is one who redoubles his efforts when he has forgotten his aim".

While America talks in high moral terms about preserving security and fighting terrorism, we should remind ourselves of the human cost of its wars, and just what sort of enterprise Shambaugh and Kleine-Ahlbrandt want China to sign up to.