In general there is much to be said about the huge amount of code that runs from thousands of sources on every machine.

Most OS comes with hundreds of drivers, many created by hardware makers all over the world, running with root privileges / kernel mode. And then you add to that all of the software that you install, developed by companies or volunteers all over the world, and running all sort of third party libraries, etc.

The chain of trust is huge. I'd be shocked if there was any computer in any US administration that wasn't running some piece of code written by a russian national.