How would an institutionalist explain why Germany has had a successful Green Party but the UK has not?

Question

Quizplus · Accepted Answer

Institutionalists would argue that Germany's mixed-PR system is more conducive to the success of narrowly focused parties like the Green Party. In contrast, the UK's first-past-the-post system tends to favor larger, more established parties and makes it more difficult for smaller parties to gain representation in parliament. Factors such as greater environmental sentiment or voter turnout may also play a role, but the institutional factor of the electoral system is likely the primary explanation.

How Would an Institutionalist Explain Why Germany Has Had a Successful