Think of a more direct democracy. I will oversimplify enough to annoy those from Switzerland:

Differing levels of law require differing thresholds. Country votes on a law, the majority above the required threshold vote it in. It becomes a national law. That is easy. What about when it fails? Then look to the state level. Did it pass the threshold for your state? Yes? Then it is a state law. Failed state level? Let’s look at your county/city/local level. Passed threshold? Local law.

Again, over simplified, but general idea.