According to US law, if a product does not qualify as being made in USA, then it must have the country of origin marked on the product itself, or the packaging it came in.
So until you see Leatherman tools with "China" or "Mexico" stamped on them, you can rest assured that they are assembled in the US.
The problem comes from the world market we have today. It's not reasonable to expect that every part, every screw, every flat washer in a knife or tool is made all in the same factory. And even if they were, then whose to say where the raw steel itself came from?
The US government recognizes this reality, and so specifies what percentage of an item must be made in the country for it to be marked "Made in USA."
California specifies a higher standard than the federal government, which is where Leatherman got into trouble. Hence the "Made in USA with U.S. and foreign components" statement.
~Bob