The US constitution doesn't set any limits on how small a state can be. This results in a wide disparity of state population and opens the door for gerrymandering state borders for political advantage. So what if the constitution stipulated that new states had to have a population equal to at least 1% of the national population? As it is right now, a new state would have to have at least 3.25 million people, that would allow Puerto Rico in, but not DC. Also, 20 states fail this test currently. The result would be a lot of states would take much longer to gain statehood or would be forced to combine with other states. Nevada could be part of California. Alaska and Hawaii would still be territories. The Senate would be far more equal in terms of representation, which I consider an unqualified positive.