Senator Burr comes through our checkpoints all the time, and he is usually Precheck, however, he comes through just like the other Precheck folks do. As for returning from a foreign destination, I think that there are probably a number of answers - was the trip U.S Sponsored, and was the individual functioning as an active representative of the Federal Government (that may mean they are eligible for diplomatic auspices)? If they are just taking a vacay, the rules (hypothetically) are the same for them, as would be for you.