if we want to keep fighting more wars.  An excellent point:

The next president, therefore, is almost certainly going to be an advocate of adding tens of thousands of soldiers and Marines. But setting aside where these fresh recruits will come from, given current recruiting woes, adding troops will have serious consequences that may not be obvious more than 13 months before the general election. And the consequences may not please antiwar Democratic primary voters. Committing to an expanded Army and Marine Corps implies spending a great deal of additional money on the military. But it also means the presidential candidates are choosing sides in an internal Pentagon dispute — and they are choosing the side that wants a military designed to fight another war just like the unpopular war the United States has been waging in Iraq since 2003.