First, their composition impacts the degree of coherence of the party system and the government's ability to reflect voters' needs. Furthermore, they shape public policies, behavior and incentives of political actors. Whether politicians depend directly on voters, as in a presidential system, or on their parties, as in a parliamentary system, to climb the political ladder, to whom they are most accountable depends largely on the procedure that elects them to office. How they might allocate public resources to connect them to their voters and even what kind of incentives there might be for corruption and/or electoral abandonment also depend on the political system in place. In a presidential system the relationship that exists between that of the voter and that of the candidates is that of a dynamic equilibrium in which politicians who have a certain caliber for "good government" turn to the voters, so that they reject the current one that could have lost that reputation to someone they believe doesn't have it. Through this process voters are able to bring to attention a series of issues they believe are important or to overturn a policy they don't particularly care about by putting into power a politician they believe will fight on their behalf.