When you're talking about a total war scenario, the US is effectively unbeatable for a lot of reasons. Ignoring the amount we spend (much of which is wasted on graft and ineffective procurement), we hold the distinct advantage of geography. We're fully capable of building a war machine all by ourselves -- we have the raw materials, the industry, and most important of all: a several-thousand mile long buffer zone between the US and any potential enemy looking to disrupt production.
China is the only real rising threat, and even then, they have two or three decades of catching up to do. And ultimately, I'm not convinced there are any resources that China and the US both covet so much as to go to war with each other: both are large, geographically diverse countries with a wide range of natural resources. The Chinese also have very little to gain by a shooting war: they will naturally eclipse the US in a global economy in the next 100 years anyway, so why bother fighting a dangerous enemy on the battlefield when you have better economic weapons?