Professor David Kimball with the University of Missouri, St. Louis has studied split-ticket voting patterns and is skeptical that a critical mass of voters will split their tickets in enough states to deliver both a Clinton victory and a Senate GOP majority on Election Day.
"Most voters simply intend to be, No. 1, in support of their party and thus aren't receptive to strategic or nuanced arguments," Kimball says. "And if they are going to split their ticket it's going to be for a candidate that is personally appealing to them, or to avoid a candidate that's personally unappealing."
Senate candidates who have successfully outperformed the top of the ticket have generally fallen into two camps. The first are personally popular incumbents like Democratic Sen. Joe Manchin of West Virginia or GOP Sen. Susan Collins of Maine, who have their own distinct brands and regularly outperform their party.
Other senators who have succeeded against the top of the ticket faced fatally flawed opponents, as Sen. Claire McCaskill, D-Mo., did in 2012 against Republican Todd Akin, who made controversial statements about rape and pregnancy.
Many of this year's GOP incumbents are first-term senators like Pennsylvania's Pat Toomey and New Hampshire's Kelly Ayotte. Campaign operatives praise both for running strong campaigns, but there is deep skepticism that either can win if Clinton decisively wins their states.
