Here's a link to a set of charts showing stock market performance for the years in which there was a presidential election with a Republican incumbent since 1892 from StockIndexTiming's web site. He also includes the year before and after, which is useful and we thank them for this work.
Stock Market Performance in Election Years with Republican Incumbents Click on this link, then scroll down to see the charts.
We're not big on comparisons since there are so many different variables to consider. But the theory would seem to be that if it is in their power, big business will step in at some point and boost the stock market this year, to help keep the November elections from destroying the Republican party.
Here's one example, 1932, in which business was NOT able to turn the markets significantly higher in time to secure the election for the Republicans, but did manage to put in a mid-year bottom and rally, although they could not make it stick. There are those (hat tip to ContrarianBear at WallStreetBear.com) who predicted, very early on in his presidency, that George W. Bush would be remembered as a second Hoover. Let's see if that analogy holds true.
The Chinese and other nations and central banks may be a significant exogenous factor (economist jargon for wild card) in this scenario.
P.S. Here's a fun fact posted after the close of trading. Bloomberg says that today was the worst first trading day of the year for stocks since 1983, AND that the Dow came within 1/10 of one percent of setting the worst opening day of trading since 1932. Poetic.