What Percentage of American Spending is for the Department of Defense and the War on Terror?

As a follow-up on my last post, I've done a little research and some rough calculations here to put things into a clearer perspective. Someone, please correct me if my math is in error.

George Bush's US federal budget request for FY2008 was US$2.9 trillion, US$627 billion of which were to be allocated to defence spending and the War on Terror*. Since 2001, the government has borrowed US$1.3 trillion to pay for "tax breaks, new Medicare drug benefits and the war in Iraq."** I will assume that this borrowing has been constant to suggest that the federal government will borrow US$163 billion in FY2008. Let's assume only US$80 billion of this is actually borrowed for the Iraq War. The actual total FY2008 federal spending then becomes US$3.06 trillion and the actual spending for defence and the War on Terror becomes US$707 billion. Therefore, if my estimates are reasonable, roughly 25% of the US federal government's spending of borrowed and budgeted funds right now is going towards defence and the War on Terror.

I personally believe there is still hope to turn this around. Adding the US$163 billion estimate of borrowed money to the US$240 billion budgeted net deficit for the year, the United States federal government has a total spending/earning FY2008 deficit of roughly US$403 billion. Therefore, if the spending for defence and the War on Terror were greatly reduced, the government could potentially begin to operate at a surplus.

*http://en.wikipedia.org/wiki/United_States_federal_budget%2C_2008 (ultimately gathered from http://www.gpoaccess.gov/usbudget/browse.html)
**http://articles.moneycentral.msn.com/Investing/JubaksJournal/TheFinancialTrapFacingTheUSChina.aspx