MINYANVILLE ORIGINAL With one huge element of uncertainty to be resolved once America officially decides on its choice of president the US stock market registered solid gains in mid-Tuesday trading.   "Equity markets in presidential election years do not follow a consistent pattern like markets in midterm election years. However median equity performance in the weeks following very competitive elections slightly outpaces performance following less competitive contests " Jan Hatzius chief US economist at Goldman Sachs said in a note according to The Street. "That said this election is unusual in that it will be immediately followed by debate ...