Of course, since we're talking about the seat of bureaucracy, there are a few catches. At some attractions you need to stand in a line for advance tickets, while other attractions waive that requirement for wheelchair-users.
Some attractions even have accessible tours.
It's truly a mixed bag, and with so many things to see, advance planning is a must. Don't despair though, as most of the attractions are accessible. You just need to learn the tricks of getting around, and the ins and out of accessing the attractions. Although most of the monuments and museums are accessible, getting around outside the main tourist areas can prove difficult. Street accessibility is generally pretty good on the National Mall, but elsewhere you may encounter steep, narrow curb-cuts, uneven pavement and unexpected street construction.