The first thing I'd do is toss the lamp out. Then I'd start looking for a
GFI that was tripped.
Bingo! Duh... I'd completely spaced the fact that GFI
protection on these branches was not with the breaker but by GFI
outlets at the head of the branches. Resetting them got me back
up... and I do apparently have a nasty short in the lamp to resolve.
