The answer is:
They will serve in the military when required.
They will support and defend the US Constitution.
They will show allegiance to the nation's laws
Basically, all naturalized US citizens are required to upheld the same obligations like the citizens that born in united states. Voting in election and volunteering in political campaigns are considered to be the right/freedom of the citizens, not the obligation. You would not face legal punishments if you choose to avoid your rights, but you could face it if you avoid your obligations.
Step-by-step explanation: