For example, those being blackmailed might not know or have any proof that it's FBI who's blackmailing them. The FBI of course has endless opportunities of plausible deniability, starting with "rogue contractor".
It all boils down to incentives: what exactly do you have to win from disclosing? What is the chance that people will believe you given that you have no evidence? And what would you even expect your audience to do about it? And how does that scenario compare to the worst that your blackmailer is willing to do?
It would be fairly easy for someone with the power of the FBI to rig the subject's incentives heavily in their favor, and to only pursue blackmail on subjects where they are fairly certain of success. At some point of proficiency a casual observer might not be able to distinguish it from lobbying!
We don't know if these things happen or not, but they're entirely possible. Stranger things have been leaked and declassified over the years.
In terms of incentives, blackmail is generally a lower tier crime in terms of likelihood of success. Think about if someone tried to blackmail you. There's a good chance you'd think "Sure I can give in to their demands now, but they'll just ask for something else later and they never have to stop asking". Unless the crime being covered up involves significant jail time, most people would rather face the consequences than live the rest of their lives under someone else's control. Many former politicians have successful careers even after mundane scandals (Weiner and Spitzer come to mind).
And depending on the nature of the secret, most politicians would get some slack from the public for having the courage to standup to FBI blackmail. They might even be able to spin themselves as a flawed hero. In fact, having a three letter agency try to blackmail you right now is kind of a get out of jail free card.
As tptacek said, this is really fascinating fiction but it's just wildly impractical in real life. Blackmail is messy and has a lot of moving parts that are difficult to control. The FBI is better off doing exactly what they do now: asking Congress for money and getting it.
Any crimes that the politicians are involved with probably do carry significant jail times, given how corruption and pedophilia apparently still exist.
> depending on the nature of the secret, most politicians would get some slack from the public for having the courage to standup to FBI blackmail
I don't really see this playing out in the politician's favor.
Politician: FBI is blackmailing me! Press: with what? Politician: ... Press: do you have any proof it's FBI? Politician: Nope FBI: We're not doing anything FBI: (anonymously releasing some info) Politician: resigns / get jailed Press: boo bad politician!
Or:
Politician: FBI is blackmailing me! Press: with what? Politician: They say I stole a billion dollars FBI: we're not doing anything, but we should investigate this FBI: wow this guy really did steal a billion dollars, we can't ignore this Press: politician announces he stole $1 billion dollars, gets jailed
I don't get one thing: if politicians' decisions can be purchased by campaign donations and lobbying, why would they be any more resistant to something more persuasive? Again, to reiterate, blackmail does not need to be letters with threats compiled from newspaper cutouts. There's a whole range of methods they could be using that rely on the information they collect.
I'm not taking a concrete position on the question, but given the secrets that plain ordinary people keep, I would not be surprised if the data available on people is used for coercion and nobody talks about it.
Were you surprised by the Snowden leaks? Even after AT&T and Room 641a?
Some smoke, but no fire.
"President Obama’s recently convened executive review of the NSA admitted: “In light of the lessons of our own history… at some point in the future, high-level government officials will decide that this massive database of extraordinarily sensitive private information is there for the plucking.”"
From:
http://www.whitehouse.gov/sites/default/files/docs/2013-12-1...
Why can I only find references to that allegation on sites like LewRockwell.com, and not on WaPo or the NYT?
> [...] information was being collected for blackmail purposes, and her lesbian relationship, and they, the Turkish entities, wanted both congressional related favoritism from her, but also her husband was in a high position in the area in the state she was elected from, and these Turkish entities ran certain illegal operations, and they wanted her husband's help. But I don't know if she provided them with those. I left. I was terminated.
[1] http://www.huffingtonpost.com/daniel-ellsberg/covering-up-th...
Edit: upon further reading it appears to not be an allegation against the FBI but rather Turkish agents which makes this much less news-worthy:
> Turkish agents started gathering information on her, and they found out that she was bisexual. So a Turkish agent struck up a relationship with her. [ ... ] I don’t know if Congresswoman Schakowsky ever was actually blackmailed or did anything for the Turkish woman. http://www.bradblog.com/?p=7429