Social Credit's popularity reached its zenith around the time of the East Coast Bays by-election.
Voting resulted in the election of Gary Knapp, the candidate of the Social Credit Party. This was unexpected, as minor parties rarely won seats in Parliament at the time; although such voting was more likely in a by-election. Muldoon blamed Brash and the party organisation for the defeat, but was strongly rebuked by the party for this stance. The loss of the by-election provided the catalyst for growing opposition within the National Party to Muldoon's leadership.