U.S. President-elect Joe Biden speaks about the U.S. economy following a briefing with economic advisers in Wilmington, Delaware, November 16, 2020.

Main Street confidence dropped again this quarter — the second setback this year and also only the second substantial decrease in the nearly four years since the start of the quarterly CNBC|SurveyMonkey Small Business Confidence Survey. The primary cause is simple: the election. Even as the coronavirus is resurging, state and local governments are again eyeing tighter restrictions, and businesses are bracing for flagging demand, it's politics that's driving economic expectations. 

From the very first quarterly survey, which coincided with the first full month of the Trump presidency, political partisanship has been an underlying driver of the rosy outlook on Main Street. More small business owners — usually about 60% — are Republicans than Democrats, and their confidence has been bolstered by the fact that President Donald Trump, a Republican, holds the highest political office in the country.