When I served in Vietnam, I was amazed that EVERYTHING the military used to build bases was from material imported from the US. Everything for sale in the PX, everything we ate, the guns, the uniforms, the toilets, the plywood, the furnature; absolutely everything was either flown or shipped in from the US.
I am delighted to hear we are finally buying some stuff on the local market. The real question here is "how much would the taxpayer pay for all that stuff we got from Russia, versus if all of it were bought in and shipped from the US?
You are not comparing apples and apples when you say,
"In fiscal year 2007–2008, the U.S. taxpayers paid more than $840 million total to the Russians. This equals what the Department of Defense would pay for four additional C-17 aircraft..."
How much would we have paid for the stuff we bought from Russia? Not all of it was transportation cost. And what is the cost for a C-17 to make a flight halfway around the world to Afghanistan? I'll bet the cost of fuel and manpower, and maintenance dwarf the capital purchase price for a C-17.
I am positive if you counted all the costs of buying that stuff from the US and transporting it to Afghanistan, it would be double the cost of what we paid to Russia. Finally somebody is thinking with their wallet.