Some EU legislative proposals are amended substantially as they go through the legislative process, whilst others remain rather unaltered. This paper investigates what factors motivate the EP and the Council to introduce changes into the legislative proposals limiting the extent of EU authority expansion proposed by the Commission. We track the shifts in the level of authority expansion from the proposal to the final act, and examine whether the conflict of preferences within and across the EU institutions drives the outcome of negotiations towards the SQ. We posit that a politicized environment coupled with the waning support for the EU involvement shape the motivations of the Council and the EP to adjust the pace of EU authority expansion to the public preferences. However, the EU legislators may respond to different groups within the Union’s population and face different time-horizons. Discrepancies between country-level support for the EU action across the member states define the extent of the inter- and intra-institutional conflicts within the Union. To avoid gridlock and legislative failure, the EU legislators will coin an outcome limiting the expansion of the EU authority. To test our argument, we identify the difference in the extent of authority transfer embedded into the text of legislative proposals and the adopted legislative acts using text analysis techniques. We draw on the Eurobarometer indicators to capture the variation in the level of support for the EU action across policy areas. Our findings have implications for EU reform capacity under conditions of policy contestation.