I'm a third generation Washingtonian, and Senator fan. My grandfather saw Walter Johnson; my dad saw Cecil Travis / Buddy Lewis / Early Wynn. I watched Harmon Killebrew start when he was 17. Yep...he might have been 24 when they stole our team (see David Gough's book), but Harmon started in Washington at 17.
The only Expo I ever saw was Rusty Staub, after he came to the Mets.
Go through a history of the Washington Senators (start with Shirley Povich's book, 1954 but recently reprinted) and you find that there were a dozen Washington franchises, named nationals, Potomac, Statesmen (?), and usually called the Senators by fans who just didn't care what the owners said.
This is another franchise...Walter Johnson pitched in DC, threw a silver dollar across the Rappahanock, Bucky Harris managed the Nats three times, and the franchise played in the American Association (?), the National League (two or three versions), the American League, and now the National League. The Expos are finished, just as the Texas Rangers have no connection to DC. Warner Wolf once predicted that the mid-80s Twins would win the World Series because "They are the Warshnin Senators in disguise", but none of his New York audience, except for me and the kids, knew what he was talking about.
Little Tavern is gone; Hot Shoppes is gone; Hogates is probably gone, the street-car tracks are gone, but they are still Washington institutions.
Consider: a few years ago, my son and I made our annual visit to MCI Center to see the Caps (the Bondra / Ollie era) and there, exhibited on the wall, was not only a Wes Unseld jersey and a Sonny Jurgensen jersey, but Harmon Killebrew's number 3.
[edited to correct for beer-erations. Happens when the Nats win. Ding! Ding! Ding! Oh, for an explanation: my Dad says that Arch MacDonald used to broadcast out-of-town games from a car-dealer show-room down-town. He would read the ticker and imitate the crowd. He would ding a bell for each hit. That's baseball over the radio back in the '30s.]