A constant scoring rule asks each individual to vote for a given (and
constant) number of alternatives and the alternative with the most vot
es is elected. A sequential constant scoring rule applies this princip
le in a process of sequential elimination. Constant scoring rules as w
ell as sequential constant scoring rules fail to satisfy Condorcet cri
teria when individual preferences are unrestricted. The purpose of thi
s paper is to show that, if we assume that preferences are single-peak
ed, then some constant scoring rules satisfy the Condorcet loser crite
rion and some sequential constant scoring rules satisfy the Condorcet
winner criterion. The results we provide make possible the identificat
ion of these rules.