Let's just have a glance at what championships D.C.-area sports teams have won...
3x Redskins (1983, 1988, 1992)
1x Bullets / Wizards (1978)
4x D.C. United if you want to count MLS, too (1996, 1997, 1999, 2004)
0x Nationals (est. 2005, 0 WS appearances)
0x Capitals (est. 1974, 1 Finals loss 1998)
I have the Capitals in the bottom-tier of NHL franchises - even worse off than us, in that they have 3 Presidents Trophy wins (QF loss, SF loss, SF loss) to 1 Cup Finals appearance which ended in a sweep. That could all change if they do the unthinkable and win it here