There's a valid and very hard to answer question about how this news -- or any potentially major news -- will affect the voting. There's also the question of whether or not the new revelation is fair for those who've already voted, as National Journal's Josh Kraushaar noted on Twitter.
Let's answer that one first.
Eighteen million people have already voted. That's 14 percent of all of the votes cast in 2012 -- a substantial number. Research conducted after the 2012 race, though, indicates that people voting early are those least likely to be swayed by new information.
In a paper titled "The Dynamic Election: Patterns of Early Voting Across Time, State, Party, and Age," Vivekinan Ashok, Daniel Feder, Mary McGrath and Eitan Hersh looked at the composition of the early vote four years ago. Among their conclusions:
[C]onfirming the longstanding view that high-participation voters are most likely to take advantage of early voting, we showed that in most early voting states, older and partisan registrants, who tend to be reliable voters overall, were indeed more likely to cast early ballots in 2012. This means that the Election Day electorate tends to be disproportionately composed of low-participation voters. Indeed, on Election Day itself, it is often the case that independents are voting more than partisans and that young voters are voting more than older voters.
What's more, "among those who do cast an early ballot, high-participation groups are voting earlier in the pre-election window than are the low-participation groups." So even when less-frequent voters participate in early voting, they tend to do so closer to the election.
In other words, people who vote more regularly are more likely to have already taken advantage of early voting. And people who vote more regularly, data from Pew Research tells us, are more likely to hold strongly partisan views.
People with strongly partisan views, it seems safe to assume, are much less likely to have their minds about the election changed by whatever the new Clinton email revelations might turn out to be.
This all makes sense. People who pay less attention to politics and vote less regularly are less likely to have made up their minds about the candidates. And undecided voters at this point are, by definition, undecided. They're not going to have cast a vote.
Maybe some of those 18 million people will now wish they had voted differently. But probably not many.
What about everyone else? How will this change things?
Given that we don't actually know what's going on, besides "something happened," it's hard to say. We do know that following the resolution of the email issue in July, after FBI Director James Comey's announcement that his agency wasn't recommending that charges be filed, poll numbers didn't move. This was right after the Fourth of July, and far fewer people were paying attention, but the poll numbers didn't change significantly until the conventions later that month.
One way this could affect the outcome is by dampening voter enthusiasm for Hillary Clinton. The personality factor where Clinton is viewed the most negatively is honesty. When Quinnipiac University asked people who viewed Clinton as dishonest why they did so, the most common response was that it was because of her use of a private email server.
Clinton's base is heavily made up of nonwhite and younger voters, who are less likely to go to the polls. Trump's team is hoping to tamp down turnout from those groups; renewed questions about the email server, however vague, could help play into that. Why rush to the polls to vote for someone who has all of these questions surrounding her, whatever the questions might be?
It is always the case, even in this weird year, that the safest assumption about the effect of a new revelation shortly after it was revealed is that the effect will be small to non-existent. Presidential races are much more likely to hinge on big-picture things, not on daily ups and downs that people on Twitter get excited about.
But then, presidential candidates are usually relatively well-regarded and rarely are mired in accusations about who groped who and whose estranged husband texted what to which teenager. And yes, that's a cop-out on my part, because I have learned by now that if the traditional rules of presidential politics are going to be broken, they're going to be broken in 2016.