Yesterday, the Dow Jones Industrial Average briefly peaked above 13,000 before dipping at the close. Like all Dow milestones, this one touched off the usual celebration. It may be no coincidence that the market is rising under a Democratic president. In a Bloomberg Government article out this morning, Bob Drummond examines the historical record and finds that the stock market (the S&P 500, in this case) performs much, much better under Democrats than Republicans. The story is subscription-only for now, but I’m allowed to post the accompanying chart, above. How big a difference does the president’s party make on investors? As Drummond shows, $1,000 invested in a hypothetical S&P 500 tracking fund beginning when JFK was president and measured only during subsequent Democratic presidencies would have yielded $10,920 by the time the market closed yesterday. Alternatively, $1,000 invested when Richard Nixon was president and measured only during Republican presidencies would have yielded $2,087 on the last day of George W. Bush’s presidency.