Obama and the 100,000
I see a fair number of people, including Brian Beutler, disquieted by Barack Obama's call for the addition of 92,000 ground soldiers to the American military. It's important to note that this has become pretty much a standard Democratic policy proposal and I'm not sure it differentiates Obama from anyone of the main legislative leaders or other presidential candidates. As to the merits of the plan, well, it depends. 100,000 more soldiers instead of . . . what? If at the margin we're trading away F-22s, Osprey helicopters, DD(X) destroyers, etc. in exchange for additional troops, that's a perfectly good idea. It would be a great idea to do what Obama proposes in regard to reducing our nuclear spending and use that money to finance additional boots on the ground. By contrast, however, further restraint in domestic discretionary spending in order to finance further increases in defense spending is a bad idea.
At the end of the day, the Pentagon doesn't really "need" more troops. The US military, however, has the luxury of operating well beyond the margins of strict necessity. More troops would be useful. They could guard refugee camps in Chad, keep girls' schools open in rural Afghanistan, let National Guard soldiers stay home with their families ready to respond to natural disasters, help monitor cease-fire lines in Congo, etc., etc., etc. If you're worried that more troops would be used for occupation duty in Teheran I think that's a smart worry, but the solution is to elect a president who won't invade Iran. As we've seen in Iraq, an absence of logistical capabilities won't stop a bad president from launching an unwise invasion.
The problem with the proposal is that "useful" is a low bar to pass. We have way more conventional military firepower than we need and way, way, way more nukes than we need. Restraining that stuff to free up money for more soldiers is change int he right direction. But we have less health care, less education, less child care, less basic infrastructure, etc., etc., etc. than we need. Cutting back there to further incease the capabilities of what's already the most capable military on the planet by a long margin doesn't make sense.