This study tests whether psychological attachment to a political party influences voluntary participation in a government-promoted public-good scheme, positing that cooperation is higher among households that identify with the party in government and lower among households that identify with the party in opposition. The focus is participation in a voluntary recycling scheme, in the context of a European country (Malta) where two parties dominate the political landscape. A nationally-representative survey (n = 1,037), yielded information on recycling participation rates and on environmental and political preferences. The survey was conducted shortly after a change in government and also gauged intent to participate in a new scheme with a split-sample manipulation in which the treatment group received a political prime. The results indicate that the initial uptake of the scheme launched by a Nationalist government was significantly lower among respondents close to the Labour Party. Five years later this effect had decayed. But intent to participate in the hypothetical scheme was lower among respondents close to the party in opposition (this time, the Nationalist Party), if primed with a cue that associates the new scheme with the Labour party. Formal modeling of scheme participation and intent (controlling for political and environmental ideology inter alia), yielded consistent results. These findings shed light on a new dimension which may be responsible for diverse rates of uptake of a public good schemes with practical implications for scheme promotion.