Does Proportional Representation make it easier for extremists to gain power?
No. Although it may make it easier for them to gain a little representation, it makes it harder for them to gain power because their representation will be roughly proportionate to their number of votes. Hitler formed a minority government after the 1933 PR election in Germany and did not gain full power until he seized it in a Putsch. Goering’s evidence in his war crimes trial was that, under the British “first past the post” system, Hitler’s Nazis would have won every seat.