The 2010 Quadrennial Defense Review provides for the following task guidance:
U.S. forces are sized to conduct the following types of operations in overlapping timeframes:
1. Prevail in ongoing conflicts in Afghanistan, Iraq, and in the war against Al Qaeda and its allies
2. Conduct “foundational activities” to prevent and deter: attacks on the United States, emergence of new trans-national terrorist threats, and aggression by state adversaries
− Over the mid- to long-term, expand foundational prevent and deter activities
3. Be prepared for other challenges
− In the near term, be able to support civil authorities at home and defeat a regional aggressor
− In the mid- to long-term, be able to conduct a range of multiple, simultaneous operations:
Stabilization op + defeat highly capable regional aggressor + support civil authorities in U.S.; or
Defeat two regional aggressors + heightened alert posture in and around U.S.; or
Stabilization op + long-duration regional deterrence + COIN + support to civil authorities in U.S.
In addition, in regard to deployment tempos for ground forces, active forces will deploy at a ratio of 1 year abroad for every 2 years at home, and reserve forces will deploy at a rate of 1 year mobilized for every 5 years at home. The actual QDR states we'll have 45 active brigade combat teams and 28 National Guard brigade combat teams plus 11 Marine regiments (8 active and 3 reserve?) as the pointy end of the stick. Plus 3 Ranger battalions and special forces. The Navy's new riverine infantry force is not mentioned, which I though pretty much added another small brigade-sized force to the mix.
The "overlapping timeframe" issue, which caused so much criticism in regard to Iraq "distracting us" from Afghanistan, will continue. Remember, we don't have enough ground forces to fight two regional wars at the same time and not be forced to deploy troops at force-killing tempos. So we've always planned to hold in the less critical theater while we go for the win in the primary theater, and then shift forces to win in the new primary theater. This is one reason why we had so few troops in Afghanistan while the Iraq War raged and why we are now shifting forces and focus to Afghanistan.
Right now, for the near term, we are planning on winning in Afghansitan and cementing the victory in Iraq, while fighting al Qaeda globally and being capable of defeating an offensive by either North Korea or Iran.
In the mid- to long-term, after we're essentially out of the warfighting business in Iraq, we should be able to cement a victory in Afghanistan while defeating an offensive by either China or Russia (I assume that is who "highly capable regional aggressor" means); or defeat North Korea and Iran (regional aggressors); or cement the victory in Afghanistan, deter Iran, North Korea, Russia, and China, and fight a counter-insurgency somewhere in a theater be named. If I'm identifying the likely names for the euphemisms correctly, of course.
These are not unreasonable objectives to aim for. Certainly it is no worse than our old "two war standard" which was never really capable of fighting two wars at once (because hardly anyone remembered that officially we specified "nearly simultaneously" as the earlier accepted term for today's "overlapping timeframe" phrase)
Now, whether the forces planned are adequate to meet these tasks are enough is a separate question. I'm worried that all of this is geared toward essentially carrying out a New Ten Year Rule for defense expenditures.