Marcellus tells us "Something is rotten in the state of Denmark." After we hear the ghost's message, how does this prove true in a broader sense for your community (Centerville, Bountiful, Farmington, etc.) ? The whole country?

It means that things are not going well at the top of the political system

Explanation:

It's trying to give the brief description of the degenerated state of political system of the country, abuse of office of power by elected officials and it's destructive effect on the people and the country in whole.