To what extent do the institutions of presidentialism allow voters to hold governments accountable? Powell and Whitten (1993) suggested that voter capacity to sanction is strong when "clarity of government responsibility" for outcomes is clear, and vice versa. I argue that clarity of responsibility functions differently under presidentialism and that presidentialism generates particular forms of accountability. In general, electoral sanctioning is weak in nonconcurrent elections, which do not occur under parliamentarism, but is stronger in concurrent elections. In concurrent executive elections the clarity of responsibility does not attenuate the economy's impact on the vote. Yet in concurrent legislative elections both partisan and institutional variables diffuse responsibility for economic performance. Thus under many common institutional and partisan formats, voters sanction presidents to a greater degree than legislators for the same phenomenon. These findings elucidate the conditions under which we might observe accountability similar to what we find in some parliamentary systems or a more uniquely presidentialist "dual democratic legitimacies" of the kind Linz (1994) imagined.