www.ballotpedia.org is an extremely useful source on elections -- especially propositions. It includes who are the backers and opponents, and who the big contributors are. But Ballotpedia "edit trolls" can alter or omit facts to suit their purposes. I just got involed in one such Ballotpedia situation on a California proposition.
It's very similar to Wikipedia in operation. Hence caution is advised.
I just corrected numerous errors in their post on California's Prop 30 (on this November's ballot) -- the "Jerry Brown" MASSIVE statewide increase in taxes (income and sales taxes).
EVERY error I found understated the cost to taxpayers, or just outright omitted damaging information concerning the prop. Coincidental or intentional?
I found that EVERY calculation on the income tax understated the percentage increase in the tax -- by a LOT. Also it failed to include the 13.3% bracket on $1 million incomes in the summary -- falsely claiming that the top bracket was 12.3% above $500,000. And it failed to mention the retroactive nature of this tax -- a November vote that will impose the income tax back to 1 January, 2012.
I'm now signed up as an editor (too easy to do). In addition to correcting the "errors" and adding important omitted facts, I also added some annotated arguments against Prop 30 in the article. The opposition arguments selected seemed to me to be particularly weak (gosh, I wonder why?).
My stuff can in turn be edited by others. We shall see if my corrections are reversed/deleted. I'm not optimistic, but I am hopeful.
I do recommend you go to the link. The info on who is funding this prop makes clear that this is a labor union-sponsored effort. The seven figure contributions from unions speak for themselves.