Conversation

Suppose you had to produce a local computer from scratch, completely independent from existing manufacturers like Intel. (If you need a specific location for this hypothetical, let's say Greater Philadelphia.) No chip fabs in China, Taiwan etc. The tech level and computing power doesn't matter, you can tailor the application to the power of the computer; indie local production is top priority.

What is the best approach? A simple conventional silicon chip? Vacuum tubes? Analog? Mechanical?