S/P/67. Are differences between party systems becoming increasingly superficial?

This essay examines the hypothesis that party systems are converging, and that any differences which do exist between party systems are merely superficial. It looks at as many credible attempts as possible at describing what form this convergence takes, why it is posited and whether it sounds reasonable in the light of data or theoretical rigour involved. This examination includes looking at the Downsian model, ‘catch all’ parties, membership figures and identity links.