The legislative institutions of the EU are subject to different pressures, which may modulate their public responsiveness and lead to inter-institutional conflict. While the directly elected European Parliament is empowered by the EU Treaties to represent the interests of the citizens across the Union, the Commission's legislative agenda may favour some interests at the expense of others, which is more likely when the public is divided or diverse interests are mobilised to influence policy. Under these conditions, we expect the EP to alter the Commission's proposals more to align it with the demands of the public. Conversely, higher public salience of policy across EU citizens should incentivise both institutions to respond to average public demands, which should be reflected in higher Commission-EP policy agreement. We expect these effects to be especially pronounced for proposals that enhance EU authority, which are more likely to come under public scrutiny. We use the Decision-Making in the EU (DEU) datasets to test these hypotheses for legislative proposals considered during the last three legislative terms (2009-2024). Eurobarometer surveys and the EU Transparency Register serve to measure, respectively, public opinion and actor mobilization over years and policy domains. We further supplement these data with the estimates of EU authority expansion within legislative proposals, obtained using semi-supervised machine learning. The results contribute to our understanding of how democratic representation affects the interactions between EU institutions in shaping EU legislation in the context of politicisation.