This November, as usual, California voters will face a slew of state propositions at the ballot box. One deserves a closer look and, we believe, should be passed. Prop. 39 would change the current system that allows inter-state corporations a choice in how they calculate their liability for California corporate taxes. If passed into law, Prop 39 would enact a system where a company's income tax liability would be based solely on its sales in California. And then for the first five years, about half of the estimated $1 billion in additional annual revenue would be dedicated to energy-efficient projects at schools and other public buildings.