"Do you mean a car designed in the US and built in China, or a Japanese car built in Ohio?" I'm pretty sure that given how few choices of mainstream hardware there are you are screwed no matter what you buy.
I've started doing the same. Of course, I wouldn't be shocked if either or both of the following were true:
1. Other countries collude with America in this practise;
2. Other countries are also practising this.
Open source is a potential solution to this problem. It doesn't guarantee security (heartbleed anyone?), but it does allow anyone, anywhere, any time (assuming capability) to verify. My router runs Open-WRT, so I feel safer.
Thinking about this more, there's a little problem for those living in "the land of opportunity": given that the government has access to all communication via its dragnet, they're aware of your purchase and can intercept it at customs. Now you might try to be smart and buy it in person while on holiday. But remember, the airport NSA can take it off your without reason and of course do what they want to it.
