Political insiders have been talking a lot in recent weeks about whether the Democrats’ vaunted turnout machine can make up for a hostile political environment. Rich touched on the subject in his appearance last night on Special Report and described the two as countervailing forces.

Neil Newhouse, Mitt Romney’s pollster, has also weighed in on the matter. Chris Cillizza at the Washington Post interviewed Newhouse recently and described him as ”the most worried Republican in Washington.” Why? Newhouse says the number of undecided and independent voters in the country has declined, and so turning out your voters has become increasingly important for both sides. As he put it: “The persuasion campaigns have been supplanted by the stimulation campaign.”

Turnout normally hinges on a combination of messaging, on the one hand, and grassroots campaigning and voter-targeting technology on the other. Newhouse seems to suggest that today, the former matters far less than the latter. But messaging, and messengers, do still matter, and I’m guessing it’s hard to win the turnout war if you don’t win the messaging war.

Democrats know the president is unpopular, but they believe in their own machine and that, fundamentally, they can make 2014 look a little bit more like 2012 than 2010, the last midterm year when voters were dissatisfied with Obama. That’s never happened before, but if it does, it will be a truly impressive feat on the part of the Democratic party.

On Tuesday, the assumptions of one side will be right and those of one side will be wrong. That will matter hugely not just for who takes the Senate, but for 2016 as well.