comprehensive article in the Post that ran July 2, the tenuous US supply lines to Afghanistan were examined WRT ongoing and future difficulty in supplying NATO forces in Afghanistan via frenemy Pakistan. Fast becoming more enemy than friend in the wake of the Abbottabad raid, the US dependence on fraught supply routes crossing over 1600 kms from Karachi to Kabul and beyond. This has been a subject of interest of mine for a while now.
With Karachi taking terror hits on a daily basis, including the attack on its naval base, and with the degree of enmity for the US at an all time high all along the supply rout, policymakers and strategists should be concerned. Indeed, its a sign of desperation that the US turned to arch Pakistan ally China in the hopes of finding an alternate route. The US is already working the imperfect northern route quite hard, which explains why insurgency appeared in Kunduz province around 2009. Indeed, the now famous air strike by the German's on a fuel tanker in 2009 signaled the shift in the once largely stable province. Its right that the US should seek alternate routes. Pakistan has a strategic leaver over the US on this issue - and their nukes. There were rumors back in 2009 that Washington even tried to cut a deal with Tehran for an eastern supply route, but ongoing Iranian weapons shipments show that dealing with Iran on this matter would be more trouble than any likely benefit.
Graphic from the Post Story cited above.