Maybe not much of a controversial topic but a handy tool for election times.
I've been using
Newsmeat for years to look up contributors but
this site has it (Newsmeat) beat .. hands down!
Once you click on the
find button at the bottom, (after you put in a politicians name) the page that comes up will be the first, (in some cases) of Many.
You'll notice an
about on the results pages under the politicians name.
Clicking on that will bring up the Largest contributors to that politician ..
which is usually someone like Bank of America!
(I've linked only to their Contributions page but the site itself offers much more!)
Find Contributions | MapLight - Money and Politics