lowering state-level fragmentation. In Hamburg, the CDU and FPD formed an anti-socialist alliance - the Vaterstädtischen Bund Hamburg (VBH) - to compete more effectively against the dominant SPD; in Hessen, the highly nationalist FDP state party merged with the right BEH by inviting its candidates to run on its electoral list. (Dittberner 1984, 1313-14; Stöss 1984, 1434) This Länder electoral alliances were not repeated in the 1953 federal election thus accounting for the increased fragmentation in those two districts; so, it was change in elite behavior, rather than strategic voting, which accounts for this anomaly.
Looking at the fragmentation of state elections following the 1953 federal election offers another opportunity to assess the effects of the new, national electoral threshold. The last column in Table 4 shows that median fragmentation increased by 0.2 parties compared to 1953 but dropped by 0.5 parties when compared with the 1949-52 state elections. Voters thus responded to the lower threshold in the post-1953 state elections by returning to smaller parties but clearly not at the same rate as during the previous round of state elections. So most likely, only a small percent of voters who defected from small parties in 1953returned to those parties once the incentives for strategic voting declined in the state elections.
Other Procedural Changes: Compared to the electoral threshold, the introduction of the second ballot, change in secondary electoral threshold, and size requirement for parliamentary caucuses had only a minor impact on strategic voting. The original electoral law granted parties parliamentary representation that won a single district but failed to cross the 5% threshold. In 1957, this secondary threshold was increased from one to three SMD; this increase was largely a concession from the CDU to the FDP which hoped to further weaken minor parties, leaving it as the only remaining swing party. (Jesse 1985, 226-27) The increase was inconsequential since small parties, facing strategic voting, never were competitive in SMD districts. For example, if we simulate the 1953 election with the 1957 three SMD threshold, the ENPP would have dropped from 2.79 to 2.7, preventing only the Zentrum from making it into the Bundestag.
The introduction of the second ballot in 1953 has frequently led scholars to over-estimate its importance. Starting in 1953, voters got to cast two separate ballots: a district