The author estimates the impact of compulsory election laws on certification success using data on over 6,500 private sector certifications from British Columbia over the years 1978–98. A unique quasi-experimental design is used by exploiting two changes in the union recognition law: first, in 1984, the introduction of mandatory elections; and second, in 1993, the repeal of elections and their replacement by the original card-check procedure. The author also estimates the effectiveness of management opposition tactics across union recognition regimes. Success rates declined by an average of 19 percentage points during the voting regime, and then increased by about the same amount when card-checks were re-instituted. The results indicate that the mandatory election law can account for virtually the entire decline. In addition, the findings suggest that management opposition was twice as effective under elections as under card-checks.