One of the candidates that has been suggested for a key registration
body is the ACLU.  I think this is poor choice.   The ACLU is
essentially a group of auditors: they audit how people's civil
liberties are administered.  Traditionally, auditors do not like to get
involved in the design or operational aspects of things, and with good
reason.

When I was a systems programmer, it always infuriated me that the
auditors would come in and tell us our implementation stunk from a
security point of view, but wouldn't tell us how to fix it.  I always
figured they just liked to critcize, without doing the work to help fix
the problem.

Then I took a stint as an auditor, and I found out the real reason.
Auditors don't like to recommend solutions, because it puts them in a
bad position if they have to criticize the implementation later.  The
auditee can say, "Well, you told us this way would be OK."  It
compromises the independence that is a necessary part of the auditor's
job.

Taking the case at hand, suppose ACLU becomes a key half registrar.
Suppose that, perhaps through some error on ACLU's part, a key half gets
away that shouldn't, and is used to deprive someone of her civil
liberties.  The ACLU gets wind of this, and wants to take it to court.
But they end up being at the same time on the side of the defendant
and of the plaintiff, which is not an easy position to be in.

There are exceptions to the complete independence of auditors: at one
place where I worked, when payroll checks were printed, they were signed
automatically by a signature drum on the bursting machine.  This drum
was kept by the auditors (who also kept the check stock), and
was brought down to Data Processing when it was time to do the checks.

I believe the difference between this situation and the key registration
situation is that it is fairly obvious when it is time to do the payroll
checks:  if they were done yesterday, and someone wants to do them again
today, he better be able to produce yesterday's checks so that they can
be destroyed.  Determining which of the many requests for key halves are
legit is a trickier process, one much more prone to mistakes that could
put the ACLU in a protecting-the-client versus protecting-the-ACLU
conflict of interest.

As always, my opinions are my own.