The continued loss of American lives taken by the Afghans they work with has added another difficult challenge to this country’s efforts to bring a modicum of democracy and civility to a country of vicious religious and tribal contests and deep political divisions.

Six coalition forces’ members were killed by their Afghan allies in the last five days, and Americans were among them.

America’s original involvement in Afghanistan after the Sept. 11, 2001, attacks was heavily conventional in nature and largely out of harms way. American advisers, electronic intelligence and air power provided the resources that the Afghans’ West-leaning Northern Alliance needed to inflict heavy losses on the Taliban and force it deep into its mountain hideouts, particularly along the border with Pakistan.

But after the return to the war in Afghanistan three years ago as the origin of the attacks on the United States, the partially re-established Taliban began to show that it had broadened its disruptive fighting techniques by incorporating some of what had taken place in Iraq.

Another step, which did not occur in Iraq, is for Afghans in uniform to ambush their coalition counterparts under conditions that usually are suicidal. Officers can be targeted in such surprise attacks, making them particularly lucrative.

Generally, the Taliban is being cited for placing its followers in positions where such attacks can take place. Recruits joining the several levels of Afghan military and police are subjected to differing degrees of screening as to their motivation, and as The New York Times reports, civilian employees may receive little or none.

It also is not hard to imagine that one or more attacks in the last two years may have been carried out by Afghans unconnected to the Taliban but harboring resentment either toward something that coalition forces were responsible for or in order to unsettle Afghanistan’s corrupt civilian leadership.

While numbers of those intentionally killed by their counterparts has been small – the Times reports 35 in 2011 and 34 confirmed so far this year – that it is happening at all is tragic. Deaths under those circumstances is an indication of just how complex the divisions are in Afghanistan, and how difficult it is for coalition forces with the United States in the majority to create a less violent environment in that country.

We look forward to the time in 2014 when coalition forces are out of Afghanistan.