Traders work on the floor of the New York Stock Exchange.

The presidential election is adding uncertainty to an already cranky stock market, and it could begin to impact prices even more as the primary season gets underway.

As Iowa held its caucuses Monday, stock prices fell on the same worries that have been driving them lower for weeks — weakness in China, disappointing U.S. data and falling oil prices. But analysts say there is also the unquantifiable effect of uncertainty surrounding the presidential election that may also be weighing on the minds of investors.