Champaign 2006: $100m for 1 proposition (#247, Topic M)

Commenting on my post on campaign spending (#231), my anonymous friend was surprised (and judging from his tone, somewhat upset) that the total would be $2.3 billion for this mid-term election. While I have no intention of further upsetting my good anonymous friend, I regret to say that that figure, although barely a week old, is out-of-date. Last evening, I heard over my car radio that the total had just jumped by more than 10%, to $2.6 billion -- and the campaign season still has 2-3 days to go. Today, I read, in a post in an investment-focused website, that, in California, oil companies have invested more than $100 million to defeat a proposition (#87), aimed at the state's getting 6% "extraction fee" (royalty) from oil companies. Up to now, as I read the post, California receives nothing, while some states get up to 15% (Texas gets 6.4%). If this proposition passes, California is scheduled to receive $4 billion a year (out of oil companies' take of $70 billion). So, the stake is high and $100 million is a small sum to pay for such a big payoff. On the other hand, while I can see the value of "investing" in campaigns that have direct cost-benefit consequences, I fail to see the rationale of investing in congreesional-election campaigns -- the cost would be higher than $100 million, but where is the payoff?