We have to spend money on a large nuclear force to help reassure allies that they won't be attacked as well as deter a direct attack on us.
We have a large portion of our military used to train, equip, and sustain our actual combat troops. Many countries with smaller armies have more brigades than we have. But their units won't be as effective and won't be able to fight for long.
And our volunteer military costs a lot in personnel costs. We do have high quality troops for that money spent, but it is a big expense.
We are not stingy in training and equipping our troops, too. That costs a lot of money. But failure to do so costs lots of blood--both ours and civilians in the area--and risks defeat.
And then there is the fact that we are far away from the rest of the world where we'd need to fight. I've noted that our ships and subs need to be larger than other countries who simply leave port and find themselves pretty much at their wartime stations. That's an expense right there. Plus we need logistics vessels and overseas bases to supply and maintain those forces. That's more money.
Strategypage noted some logistical statistics that reflect our need to spend huge effort just to be overseas--before we even start to spend money fighting overseas:
The U.S. Department of Defense is the largest user of logistical (moving supplies) services on the planet. Last year, for example, the Department of Defense used 84,906 flights to move 1.9 million passengers and 598,000 tons of cargo. Aerial refueling required 20,870 sorties by aerial tankers, which transferred 573,000 tons of fuel to 83,169 aircraft and helicopters.
Using sea transport 568,000 cubic meters of cargo was moved. There were also 37,712 pallets of munitions and 46 million barrels of fuel moved by sea. Civilian contractors moved half the air cargo and 67 percent of the sea cargo.
Nobody else has this capability to move people and stuff at this scale and with such skill. And it costs money. Be grateful that our geography insulates us from direct threats from nations that don't spend money on similar logistics capabilities rather than complain that we have to spend money to go long distances to fight our enemies away from our own cities.
And be grateful that we aren't Europe which spends a pretty sum on defense but finds that the first 95% (figuratively speaking, I'm just illustrating) of their spending goes to a civil service organization that happens to wear a uniform. They never really get around to spending money on much of a deployable fighting force.
