I voted parliamentary republic, although thats not exactly my choice.
My choice is simple, its what the United States is, at its core, although its been corrupted over the past 2 centuries: A Constitutional Republic, where no law can be passed, or be enforced legally without being expressly obedient to the Constitution that created the Nation. And, in order for the Constitution to be amended to allow such laws, the entire population must take a vote on the amendment