Finally, EU institutions and policies can become locked-in not only as a result of change-resistant institutions from above, but also through the incremental growth of entrenched support for existing institutions from below, as societal actors adapt to and develop a vested interest in the continuation of specific EU policies. In the area of social policy, for example, the European Court of Justice (ECJ) has developed jurisprudence on issues such as gender equity and workplace health and safety that certainly exceeded the initial expectations of the member states; yet these decisions have proven difficult to roll back, both because of the need for unanimous agreement to overturn ECJ decisions and because domestic constituencies have developed a vested interest in their continued application.
At their best, historical institutionalist analyses offer not only the banal observation that institutions are ‘sticky’, but also a tool kit for predicting and explaining under what conditions we should expect institutional lock-ins and path-dependent behaviour.
More specifically, we should expect that, ceteris paribus, institutions and policies will be most resistant to change: where their alteration requires a unanimous agreement among member states, or the consent of supranational actors like the Commission or the Parliament; and where existing EU policies mobilize cross-national bases of support that raise the cost of reversing or significantly revising them. Both factors vary across issue areas, and we should therefore expect variation in the stability and path-dependent character of EU institutions and policies. To take one example, the EU structural funds might at first glance seem to be an ideal candidate for path-dependent behaviour, much like the CAP. By contrast with the CAP, however, the structural funds must be reauthorized at periodic intervals by a unanimous agreement among the member states, giving recalcitrant states periodic opportunities to veto their continuation.
Furthermore, because the structural funds are explicitly framed as redistributive transferring money from rich states and regions to poor ones, we see an uneven pattern of reliance upon and support for the structural funds among member states and their citizens.