In a recent WSJ article, two academics proposed a solution as to why the stock market tends to do better under Democratic presidents as opposed to Republican presidents.The two academics featured propose that Republicans, being the “low-tax party,” are more likely to be favored in an environment where risk aversion is low. The thinking is that if risk aversion is low, more people are more apt to become entrepreneurs and vote for the low-tax party. On the other hand, when risk aversion is high, the opposite is likely to be true.Hence, Republicans under this model would be elected during times where risk aversion low. When risk aversion reverts to the mean, then stocks would suffer accordingly.My OpinionI believe it’s just a matter of coincidence why stocks tend to do worse under the traditionally more business-friendly party. One can argue that there’s a sufficient enough sample size to spin it into the idea that Democratic presidents are simply better for the market, but I think that’s a stretch.If we take out the market blow-ups during the Hoover administration (1929), George W. Bush (dot-com and financial crisis), and run-ups during the Clinton and Obama years, there is essentially no difference.For example, we know now that the increase in the stock market during the late-90’s (Clinton) was nothing more than a bubble. In the record books, Clinton gets the credit for the very fake market gains, but Bush is docked because the bubble popped on his watch.The market recovered during the Bush years before another near-60% loss during the financial crisis. In the name of oversight, we can pin some of the fault on the Bush administration, despite the fact that the original legislation that pushed for credit loosening among risky borrowers originated in the previous decade. Some of it was also facilitated by central bank policy, where rates were negative in real terms during a stretch running from 2002-04 that helped fuel an excessive expansion in the real estate markets, particularly to subprime borrowers.Stocks went on one of the best bull runs in history throughout the Obama years, partially due to how oversold they initially were and from eight years of a combination of ultra-low rates and trillions of dollars’ worth of quantitative easing from developed economy central banks. Obama’s total also rose another ~8% from election day 2016 through Trump’s inauguration, much of which was attributed to expectations of forthcoming expansionary fiscal policies.How the market will do under Trump is uncertain. I think it will greatly underperform the 15%+ annual gains experienced during the Obama years. I currently have the equity risk premium of the market at 3.15%, or the expected forward return of stocks over 10-year Treasury yields. At a 2.44% 10-year yield, that gives 5.49% in nominal forward returns, or around 3.5% in real returns. A negative credit-related event will likely be needed to generate a market correction.