Is Gridlock good for stocks?

There have been a number of questions recently about gridlock in Washington and if this is positive or negative for equities. This piece from NYT walks through some of the data. The more recent periods of gridlock (Reagan and Clinton) seem mostly positive but longer term timeframes provide different results. The best paragraph is about halfway in where he quotes some research that says "more than 90% of the price gains in the 108 year history of the Dow Jones Index through 2006 came on days when Congress was out of session". That sounds just about right.