Favorable returns come from which party runs the Senate, not White House: Wells Fargo's Chris H

Chris Harvey, Wells Fargo Securities head of equity strategy, and Liz Ann Sonders, Charles Schwab chief investment strategist, join 'Squawk on the Street' to discuss why the Senate elections may be the most certain of the week, if the historical trend of a higher S&P post-election makes sense, and how the market would react to a contested election.