(dis)agreement with "all politics is local"

[Laurence Horn]

With yesterday's resignation in disgrace of our governor, John
Rowland, the lieutenant governor Jodi Rell will be sworn in soon as
the new governor of Connecticut.  In an interview on tonight's local
news Gov-to-be Rell was asked whether she thought the scandal would
hurt Connecticut Republicans in the upcoming election in November.
She said not to worry, she has always liked the point made by a
Democrat [unidentified, but I assume she had Tip O'Neill in mind],
"All politics is local".  She went on to say that while the grammar
was bad, she agreed with the sentiment--voters will decide on their
local state senate races and so on based on the individuals, etc.

For Rell, "politics" is evidently a collective plural, so that it
really *should* have been "All politics are local" instead.  Or is it
the "all" that she thinks makes it plural?  Would we say "All
linguistics are tricky"?  "All mathematics are hard"?  (Note that
it's not purely a formal question --while it is indeed possible to
have "all statistics are biased", that's a real count noun, the
singular "that statistic is biased" being impeccable as well.)

Checking google, I find that Gov-to-be Rell is far from alone.
Indeed, there are 3040 hits on "All politics are local" to 13000 for
"All politics is local", although presumably not everyone in the
former camp would share the view that the singular represents bad
grammar.  I just hadn't realized the plural here was as popular as it
appears to be.

Larry