Presidentialism, elections and representation

How does presidentialism affect various forms of representation? All else being equal, presidentialism is likely to impede the prospects for 'mandate' representation but enhance the prospects for 'accountability' representation. The degree of mandate or accountability representation is a function of the balance of powers and the degree of separation of purpose between the branches. Strong presidentialism works against mandate representation by freeing the president from his/her legislative copartisans and promoting 'policy switching'. In contrast, a high 'separation of purpose', defined primarily by a country's electoral institutions, clarifies for voters the responsibility of each branch for policy. Thus presidentialism - under certain common institutional configurations - provides accountability representation to a degree overlooked by existing research.