Actually - there are several missions
Article I - Section 8
(Note: I have slightly paraphased)
2) regulate Commerce with foreign nations...
3) establish uniform Rule of Naturaliztion...Bankruptcies...
4) coin money...fix standard of weights and measures....
5) Punishment of counterfeiting
6) Establish Post Office and Post Roads
7) Promote Science and Art... exclusice rights (ie copyright)
8) Constitue lower courts
9) Punish Pirates
10) Declare War
11) Raise Armies ...but no more than two years)
12) Provide a Navy (no time limit)
13) Make Rules for land and naval forces
14) Calling forth the Militia
15) Organizing the Militia
16) Control Washington, DC
17) Make Laws...
6 of 18 (1/3) deal with the military.
The Feds have a big job - with the items listed - they do not need to add anything else