Which function of government stated in the preamble is consistent with the notion of having government-provided police protection?

The answer is "ensuring domestic tranquility".

Domestic tranquility for the most part implies peace at home. It can be implied with reference to family and in addition states. Domestic tranquility with respect to constitution is alluded to peace among the states. Constitution offers power and jurisdiction to national government to destroy resistance and to smooth strains between states.