How can the Resistance exist when the Republic still existed?

This one is another head-scratcher, which can show that the Republic and democracy weren't completely reinstated.

For example, if an organization such as the First Order appears, then the Republic must have its own means of fighting it, without the need of a Resistance (which, in this case, becomes nothing more than a group of vigilantes, who are also functioning outside of the law).

But then again, this is a question directly tied to the ones before it. However, unlike the former ones, we don't believe we will find an answer for it. Simply because this would mean the return to the tedious and boring spectacle offered by the prequels.