The worst kind of story for any politician is one that affirms a perception or impression that voters already have of you. And that, quite simply, is why FBI Director James Comey's takedown of Hillary Clinton's long-told story about her private email server is so damaging to her as she prepares for the fall general election campaign against Donald Trump.

Check out this chart via Gallup in which people were asked to say, unprompted, what first came to mind when thinking of Clinton and Trump:

More than one in four people said that Clinton was dishonest or unethical. One in four! More than double any other word or phrase! In an unprompted question where they could pick out literally any phrase — positive or negative! And, remember, this poll was in the field well before Comey delivered his scathing critique of Clinton's email practices on Tuesday.

How do you think people will feel about Clinton's trustworthiness after a steady diet of this sort of stuff over the next four months of the presidential campaign?

Voters were already inclined to believe that Bill and Hillary Clinton stretch the rules to their benefit — sometimes to the point of breaking. When the FBI director comes out and says that rules were violated in how Clinton handled her email server and that several pegs on which she hung her defense — no classified information sent or received, no possibility of hacking — are simply not accurate, it affirms and hardens that view.

As I have maintained for a while now, all of the above may be a moot point because Clinton is running against Trump, who, in addition to his own struggles on questions of honesty and trustworthiness, displays a recklessness as a candidate that should deeply worry Republicans.

If Trump was running even a moderately orthodox campaign, he would spend every day between now and Nov. 8 reminding voters of the gaps between what Clinton claimed about her email server and what the FBI investigation found. There's enough there — when you consider that voters already believe the worst about Clinton on matters of trust and ethics — to run a remarkably effective general election campaign.

In the hands of someone other than Trump, Tuesday's revelations about Clinton's email server would be pure political gold. In Trump's hands? Who knows.