Sustaining surges

A few weeks ago, the Washington Post reported on recently approved troop increases.

The president agreed to send 4,700 troops to Iraq in addition to the 21,500 he ordered to go in January, mainly to provide support for those combat forces and to handle more anticipated Iraqi prisoners. He also decided to send a 3,500-member brigade to Afghanistan to accelerate training of local forces, doubling his previous troop increase to fight a resurgent Taliban.
... the latest troop increase in Afghanistan had not been known and will bring U.S. forces there to an all-time high.

A recent article in Wired parenthetically mentioned intended long-term troop increases.

The Bush administration wants to increase the overall size of combat forces by 92,000 people over the next five years.

Given that the projected increase (92,000) is significantly larger than the combined surges (26,200 net for Iraq; 7,000 net for Afghanistan), the intent is apparently to be able to better sustain counterinsurgency operations on a scale comparable to what is going on currently, since it will better enable timely rotation of troops.