Only land war that might happen in Asia would be North Korea. Any conflict with China or anybody else will be nothing but naval power and possibly airforce based from allied countries, there is no point in a ground war there. Really, the brass doesn't see any political will to enter into any large-scale ground conflict at all for the indeterminate future. There will be no WWIII or massive land war, at least no land war the restructured Army could'nt handle. Who the hell has the money or ambition for that anymore? This need for massive manpower was for fighting counter-insurgencies and occupying countries. The brass has decided nation-building counter-insurgencies suck and the US is through with trying to start them, wage them or win them.
Anyways, the Army downsizing isn't that bad. They have had retention control or "up or out" forever, they just lowered the years you can serve before you are considered for discharge. You used to beable to stay as E-5 Sergeant for 20 years, untill you retire, now its 15 years and it honestly does not take 15 years of active duty service to make E-6, some soldiers do it in 6 years. They are just kicking out the marginal performers and the guys that don't really want to be in the Army anyways. There is always the National Guard or Reserves for these guys if they still want to serve.
The brass really expects to meet the new reduced quota mostly from kicking people out for misconduct- drug/alcohol problems, DUI, criminal offenses, ect. They used to do rehabilitation and non-judicial punishment for that, now it leads to a discharge 99% of the time.
The Army has all the people it needs and recruitment is very easy with the shitty economy. It is only taking the best people anymore. The other services have downsized already in the last few years, since the wars in Iraq and Afghanistan haven't justified a military need for too many jet fighters and warships. Now with Iraq over with and Afghanistan coming to an end, there isn't much military need for soldiers and Marines either.