"To state the obvious: The valuation of an individual stock reflects the collective expectation of investors about a company's future profits, dividends and appreciation, and the same is true of the market as a whole. These profits, in turn, are greatly influenced by government policy on taxes, spending, subsidies, environmental and other regulations, labor laws, and the corporate legal climate. Investors have heard enough from both candidates in the last month or two to conclude that prospects for a flourishing, competitive, growing and reasonably free economy in a McCain administration are bad, and in an Obama administration far worse. (In fact, the market's bearish behavior over the last couple of months pretty closely tracks Barack Obama's gains.)"
Read the whole thing.