For years US military personnel favored Republicans. I was not always clear on why, I have to admit, and my stepfather was a clear exception to this rule. He fought in WW II and Korea, retired the youngest Lt.-Col. in the history of the US Army (at least up to that point) and taught at Westpoint. And was a lifelong Democrat who in his retirement took to reading The Nation. But the fact was that most US military personnel were Republicans.

That has changed starting in 2002 and as of this year deployed US military personnel have donated to Obama 6:1 over McCain.

From the above linked Daily Kos Diary:

Here are some key talking points:

1. US military 2008 presidential campaign donations, from deployed US troops, favor Barack Obama over John McCain by a 6:1 margin.

2. The Open Secrets study was comprehensive - as ABC notes, "The center tallied money from donors who list the Air Force, Army, Marines, Navy and National Guard as an employer".

The Democratic Senators unanimously support a new GI Bill to help returning Veterans, providing them with full tuition, room and board to give them more education opportunities.

George Bush, John McCain, and all but 9 Republican Senators are oppsing this support for Veterans, going so far as to threaten a fillibuster to prevent a vote on this.

General Wesley Clark, Robert Greenwald, and Captain Jon Soltz are joining together to demand Republicans support our Veterans:

I think it is useless to try and get McCain behind this. Ironically McCain, along with most Republican Senators, get very poor ratings from Veterans and Solder advocacy groups. From Project Vote Smart, here are John McCain's ratings on Veterans' Issues from 2004 on: