In May 2000, the European Parliament proposed the adoption of the phrase “Unity in Diversity” as the official motto of the European Union. Although the motto was part of the failed Constitutional Treaty, it was omitted from the Lisbon Treaty. Nevertheless, EU officials and a surprising number of academics regularly employ it to characterize the EU. Like much political rhetoric, this slogan offers the prospect of reconciling competing claims, while assiduously steering clear of any concrete proposal as to how this might be done. Yet the tensions within this rhetorical formula remain. At some level, each must place limits on the other—if one prioritizes unity, that will set limits to the level and type of diversity, and vice versa. Once one moves from rhetoric to the realities of policy and treaty making, these tensions and the choices they entail cannot be put to one side. As the English saying goes, “one cannot have one’s cake and eat it too”—or, in deference to the predominantly German authorship of these two books, as the Germans put it, “one cannot dance at two weddings at the same time,”

As Daniel Finke and the coauthors of Reforming the European Union note, the very diverse features and preferences of the 27 (now 28) member states had seemed to make the EU not only increasingly unworkable as a united political organization (and ever more so as yet new member states joined), but also apparently impossible to reform in a more coherent direction. This book traces the eight years of repeated failures and ultimate success between the drafting of the ill-fated Constitutional Treaty in 2001 and the successful ratification of the Lisbon Treaty in 2009. At the heart of the book is the puzzle of why it proved possible to reform the EU with 27 members when reform efforts had repeatedly failed with 15—after all, it may be hard to dance simultaneously at 15 weddings, but 27 ought to be almost twice as difficult. The standard account of institutional change has drawn on evolutionary biology and conjectured that it takes the form of “punctuated equilibrium,” whereby a period of stasis is followed by rapid change. However, the authors note that in the EU, stasis was followed by painstakingly slow change.

The stasis is easily explained, even if the explanation flies in the face of the received wisdom of both neofunctionalist and intergovernmental theories of integration, with the one assuming that change follows naturally from functional imperatives and the other that the bigger states will call the shots. If either of these accounts held, one would have expected reform to have occurred sooner. However, because in a consensual system even quite small players who favor the status quo, or whose populations do, will be able to block major reform, it did not. The puzzle is why change—especially quite radical change—should have come about, given that over this period the number of potential veto players grew as enlargement swelled the ranks of those inclined to a more skeptical position, while a number of political leaders felt obliged to ratify agreements via the far riskier process of referenda rather than through parliamentary votes, where one would expect a government to be able to have a built-in majority.

In investigating this puzzle, the authors explored the full range of actors involved, both domestic and European, built up a database of their shifting preferences regarding reform, and covered the whole lengthy process, rather than looking discreetly at a single stage as earlier studies had done. As such, this is by far the most comprehensive account of the reform process. Their most generalizable conclusion is that if a majority of political leaders are convinced that reform is necessary, then ultimately they will get their way. That said, as their analysis shows, there are plenty of contingent obstacles able to block the path to reform, so that politicians need not just virtu but a fair dose of fortuna to get their way.

This book looks at the pre-Eurocrisis period, and although it was published in 2012, the crisis is not mentioned even in the conclusion. The normative assumptions of the authors are also largely unspoken. However, their underlying empirical supposition is that reform was necessary given enlargement if diversity was not to overwhelm unity, a view they then show to have been widely shared among the key actors, and that Lisbon marks a step change in this respect. Having taken almost a decade to get this result, these same actors wisely believed that it would be best to wait another decade before risking reopening the Pandora’s box of reform. That hope began to unravel almost immediately as the sovereign debt crisis rocked the Eurozone from 2009 onward, forcing the 17 members of the Eurozone into a series of actions that contravened both key clauses of the Lisbon Treaty, notably the no-bail-out clause (Article 125 of the Treaty on the Functioning of the European Union), and the decision-making procedures of the EU, with the Troika, consisting of the European Commission, the European Central Bank, and the International Monetary Fund, sidelining the newly empowered European Parliament in most of the key decisions.

Part of the problem lies in the fact that Lisbon did not change the terms of what might be called the underlying political contract of the EU. That contract still depended on the EU passing decisions in as consensual a manner as possible, which basically entails dancing at 28 weddings at the same time. In other words, to be credible, the commitments made by each of the member states must not only treat each state fairly but also be acceptable in the long term to the citizens of each member state. That is a high threshold to meet, and has depended on the EU operating in areas that are win–win, not necessarily to the same extent for every member state or for each and every policy but at least Pareto optimal taken overall. In other words, you can dance simultaneously at 28 weddings so long as you can have your cake and eat it too.

The Eurocrisis has subverted that scenario. The Italian version of the saying is “the wife drunk and the barrels full.” Unlike the German and English versions, it describes wishful thinking that is not literally a logical impossibility. Effectively, low interest rates for the formerly weak currency states and low inflation and low exchange rates for the formerly strong currency states, notably Germany, allowed both to drink fulsomely from the barrel while the drunken wives in the form of the governments of the member states lived the good times and progressively deregulated the financial sector. When disaster shook the banking system, the wives sobered up but the barrel was empty. The solution desired by the Troika is to force fiscal probity on all members of the Eurozone, even though, strictly speaking, excessive public as opposed to private borrowing and spending had not been the root cause of the crisis. Their chosen instrument is to entrench neoliberal policies in the constitution of each state. As a result, they hope that there will be no more weddings to dance at, as the key decisions will have been isolated from domestic politics.

Whether or not this settlement can be sustained, even if political actors are able to secure it in the short term, is a moot point. Normatively, though, it is undoubtedly contestable—as protests by not only Greek and Spanish citizens show, but also the decisions of constitutional courts—most vigorously by the Portuguese but also the Germans. The Crisis of the European Union joins in this protest largely by restating rather than confronting the rhetoric of “Unity in Diversity” in the language of high theory. Jürgen Habermas claims that the citizens of member states have a dual constituent power—at the member state level and at the EU level, as European citizens. He proposes that they retain the former as a break on the EU’s introduction of constitutional standards that are below the level of the member states, while exercising the latter in a more direct manner to build civic-social solidarity of a pan-European kind. He blames, implicitly at least, the governments in the European Council as the main agents blocking progressive reform. Yet he neglects the fact that by and large they are responsive to the anticipated reactions of their voters, as well as attempting to act responsibly with regard to financial markets. Indeed, as the authors of Reforming the European Union show, they have been the main agents of change.

Habermas is certainly right to indicate that any solution to the crisis must be democratically acceptable to be credible in the long term. However, he greatly understates the challenges to the achievement of such democratic support in a situation where everyone fears an outcome that is lose–lose. The sober wife is guarding the barrel and the wedding cake is eaten but the need for simultaneous dancing is far from over.