This is an increasing problem throughout the west. I was listening to a UK ex-politician (Phillip Hammond), who was the Chancellor and Foreign Secretary in the past.
His view, which I broadly agree with, is that the membership of a party (Tory, Labour, etc) are further from the mainstream "centre ground" than the general population, and that's a bad thing. His solution was the leadership of the party should come from the elected representatives (the MPs) and not the 100,000 "enthusiastic" members -- in the past the parties (Tory and Labour specifically) had massive membership, but now it's just a small number. It's relatively easy for a specific group to actually take over a party.
However I don't think that the small number of votes is the only problem -- the US doesn't have that problem for example, are driven by the views of millions and still come out with the less centrist options
His view, which I broadly agree with, is that the membership of a party (Tory, Labour, etc) are further from the mainstream "centre ground" than the general population, and that's a bad thing. His solution was the leadership of the party should come from the elected representatives (the MPs) and not the 100,000 "enthusiastic" members -- in the past the parties (Tory and Labour specifically) had massive membership, but now it's just a small number. It's relatively easy for a specific group to actually take over a party.
However I don't think that the small number of votes is the only problem -- the US doesn't have that problem for example, are driven by the views of millions and still come out with the less centrist options