A reader writes:
You mentioned that North Dakota had 650K residents, and Alaska 700K. But Vermont has only 621K, and Wyoming comes in at just 521K - much less than D.C.'s 600K.
One practical problem with either granting statehood to DC and doing the "carve-out" for the federal enclave area or doing retrocession to Maryland with a similar enclave, is the 22nd amendment, which grants 3 electoral votes to "the District containing the seat of government." Therefore, no matter how you defined the enclave, such a district is going to get 3 votes for President, regardless of how few people live there. And such a district will inevitably include the White House, and probably a scattering of people who live down by the Capitol. So unless you repeal the 22nd amendment - and everyone talking statehood or retrocession is explicitly trying to avoid the need for an amendment - that small group of people (maybe the President and his family alone!) will control 3 electoral votes.
Making D.C. a state would nullify the entire point of having the district in the first place. It was established so that the Federal government could conduct its affairs outside of any state regulations that would wield constitutional authority over those lands - lest Congress have to pass a specific overriding law every single time they wanted to do something that Maryland didn't like.
The real problem was allowing anyone to establish residency in D.C. in the first place. They should have Maryland annex the residential areas, with proper compensation for the costs associated with it. In places where that's not feasible, simply tell the people that they're not residents of the district anymore. Even people living on military bases cannot claim the Federal property as their place of residence. They have to pick a state. Why should people in D.C. be any different? They can pick VA or MD and be done with it.
But 50 is such a nice round number!
(Image composed by Matt Yglesias.)