Downs (1957) has proposed that new political parties may be formed in order to change the policy positions of established parties. Rather than seeking to implement their own manifestos directly from government office, some new parties may seek to influence the manifestos of established parties in order to see their policy goals realized. While the notion is old, it has not been studied extensively. This paper seeks to find out under what conditions established parties take over policy positions specific to new parties. It looks at two points in time when an established party can do so: in anticipation, i.e., before a new party enters parliament, and in reaction, i.e., after a new party has entered parliament. To this end, the paper will study the anticipatory behaviour and reactions of all established parties to all new parties entering the Dutch political system since 1946.