Members of the European Parliament (EP) from national opposition parties leverage parliamentary questions to hold governments accountable for failing to implement EU policy.

This study argues that EP oversight mechanisms are uniquely utilized by MEPs representing these parties. Analyzing a new dataset, we find they disproportionately target their own countries' non-compliance with EU law through such questioning.

Contrary to conventional wisdom about legislative gridlock, our findings suggest national opposition parties strategically employ parliamentary questions not just for political posturing but as an effective tool influencing Commission enforcement actions.