The logic of a caucus system, as against a primary, is that in principle anyway it seeks to ensure that decisions are made on the basis of discussion and the sharing of information rather than merely on pre-judged and pre-packaged opinions.

There is some analogy with a jury system - and a jury system that relied on people coming in and voting "Guilty" or "Not Guilty" on the basis of what they had read in the papers would not be a very desirable one.

The difference is that juries are not self appointed. Perhaps a system of citizens juries for selecting candidates might have some merit.

But seen from the perspective of British politics the caucus idea does have a lot of appeal. We generally don't get any say at all in picking (or rejecting) candidates in advance of the election itself. That even applies to people who are member of political parties, as often as not.