(CNN) On Sunday afternoon, with less than 48 hours to go before the start of Election Day, FBI Director James Comey wrote a letter to Republican chairmen of congressional committees stating that the emails found on Anthony Wiener's computer have not changed his judgment that Hillary Clinton should not face criminal charges over her handling of emails. Princeton professors Julian Zelizer and Sam Wang exchanged their own set of emails on the topic. Here's an edited version:

Julian Zelizer: The biggest nonstory comes to an end. It's interesting to think, though, whether this announcement does much: meaning the Trump believers believe something is fishy anyway. Were there so many undecideds really on the fence waiting to hear from Comey?

Sam Wang: There is no denying that Clinton took a hit of several percentage points after the Comey announcement. That's despite the fact that it was entirely possible that there were nothing more than copies of already-known emails sitting on a laptop. This is how email works. But email is just technical enough that it's easy to spin into a serious-sounding story.

In my calculations, Hillary Clinton's odds of winning the election were never seriously affected. The real effect was down-ticket: as I've written , Senate and House voting follow the presidential vote up and down. Five Senate races are currently within 2 percentage points: Indiana, Missouri, New Hampshire, North Carolina and Wisconsin. The Comey story may have cost Democrats between one and three Senate seats.

Zelizer: That seems like a significant move downward given how stable the polls were. Clearly it energized Republicans to stay home (supporting Trump) or to come home. If that is the impact, it's big, since without Democratic control of the Senate, she won't have much of a governing environment.

It also will fuel distrust and anger with Clinton post-election, if she wins, because within some Republican circles, the second Comey announcement won't make that much of a difference. This is an environment where people choose to believe the parts of the news that fit their narrative.

One thing for certain, there will be a lot of interest in looking into what went down at the FBI, don't you think?

Wang: A detailed look at national polls suggests that more of the change was Trump's vote share coming up, maybe because a few reluctant Republicans are coming home to their nominee.

As far as people believing what they want: That's the story of polarization. Every news story gets filtered through the ears and minds of the individual audience member.

This has to be bad for the FBI. If Comey's initial letter was forced by the threat of leaks within his agency, it means that he doesn't have control over agents who were bent on releasing damaging information about Hillary Clinton. It's not clear who will investigate this, though. The House will stay Republican. In the Senate, the odds slightly favor Democratic control, even after all this. Which party will want to get into this?

Zelizer: That's a fair point. Nobody ever likes to investigate the FBI for other reasons; namely they don't want to become the target of investigations.

The echo chamber effect is an important part of polarization. There are many good studies about the more partisan media that show how listeners and viewers are caught in the world of the pundits who spin the news through their particular perspective. This is the kind of story that I bet fits into that pattern, particularly this new Comey letter, which will at best sound like some kind of corrupt bargain to more conspiracy-oriented voters.

I do think whether it is fair or not, that Clinton, thinking about a potential presidency, needs to figure out why these kinds of attacks (about corruption) seem to affect her so much. If she is elected, that won't end when the new term begins (rather than a honeymoon she will face something more like an investigative-fest) so she will need to figure out how to contend with this.

The new Comey letter might help Democrats in some contests like New Hampshire just because the next 24 hours of the news cycle will be about this new Comey statement rather than trumping up the closing narrative.

Isn't it possible that it encourages Democratic voters to turn out on Tuesday? The attacks on what Comey did with his first letter seem to have energized Democrats in a way that the candidate herself had not. Maybe this will complement the get-out-the-vote efforts in key states like Pennsylvania.

Wang: There is no question that Democrats are highly exercised over the disclosure. I would not presume to say what the net effect would be.

Early voting suggests that in key states, Clinton is performing at least at the level of Obama in 2012. This includes Nevada and North Carolina, states with key Senate races. Overall it appears that Clinton may outperform her final polls.

If Democrats get Senate seats in Nevada and North Carolina, plus another where they have a larger lead such as Pennsylvania, that gets them to 49. To get to 50, they only need one of the following: New Hampshire, Indiana, Missouri or Wisconsin. So if Clinton gets to put up an FBI director nominee, it may well be to a Democratic Senate.

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Zelizer: It's interesting to see movement in the Senate. Under that scenario, the confirmation process would be a mechanism for talking about what happened in the election without some kind of full-blown investigation that would obviously make some Democrats nervous, especially about opening the door to "weak on national security" arguments from the GOP.

If this scenario unfolds, it could be a version of 1980 when Republicans won control of the White House and Senate, but not House. That time Reagan was able to find some space to move legislation (until the 1982 midterm elections), particularly with his historic tax cut.

The difference of course is that Reagan was connected to a vibrant conservative movement and his victory was perceived as a mandate for conservatism. Reagan thus came in with more political energy behind him than Clinton would if she is elected. The question is whether she could somehow turn her situation in a positive direction regardless of the approval problems she faces.