How come the stock market has been tanking ever since Republican insurgent Scott Brown took Teddy Kennedy's Massachusetts U.S. Senate seat Tuesday in the upset of all upsets?

I've been saying for the last nine months, most recently just before Christmas, that the secret behind the historic stock market rally from the March 2009 bottom has been the failure of the Obama administration and the Democratic Congress to ram through their budget-busting anti-growth agenda. So now that Brown has denied the Democrats their filibuster-proof majority in the Senate, and a wave of anti-incumbent sentiment seems to be sweeping the land, why would stocks suddenly go down?

Remember, historically, on average, stocks have done best under divided government -- when the presidency, the Senate...