Art Cashin, UBS director of floor operations at the NYSE, said the midterm election results are the next catalyst to move stocks.
He questioned: What will be the Republicans' idea? Will they [the GOP] try and investigate the IRS? Or will they try to pass bills and make the president look like he's the obstructionist?
"The one thing we're [markets] kind of leaving out: Does the president have any latitude with the lame-duck Senate?" noted Cashin. "If he clearly loses the Senate, will they try and push through some appointments in other things? Could be a lot of surprises out of this."
Stocks rallied Monday morning after a strong October ISM manufacturing report and the fact that it is the start of a new month, which usually gives stocks a boost. News that major oil exporter Saudi Arabia is raising prices for Europe and Asia lifted WTI crude oil midday, which in turn took stocks higher.
Major averages reversed course in the afternoon, though, as the market seemed to call Saudi Arabia's bluff. Oil prices have been falling amid slowing global growth, especially in Europe and China, and deflation concerns; therefore, it is unlikely the Saudis are going to get away with hiking prices, especially when there is such a glut of oil.
Once the markets digested the news, WTI fell to $78, hitting a two-year low and dragging down stocks with it.
Read More Cashin has been highlighting for several weeks that WTI below $80 could put downside pressure on stocks, as we've seen today.
—By CNBC's Kristen Scholer.