Complex sentence: In the past, these factors unquestionably influenced turnout in many nations, but nowadays the consensus among political scientists is that these factors have little effect in Western democracies when education and income differences are taken into account.
Split into simpler sentences: In the past, these factors unquestionably influenced turnout in many nations. Nowadays, the consensus among political scientists is that these factors have little effect in Western democracies when education and income differences are taken into account.