Brussels – With the final allocation of portfolios within its executive branch, the European Commission, the European Union has completed its change of guard. The process took almost four months, following the European Parliament election in late May, and the end result was inevitably based on a series of compromises – to be expected for an EU of 28 prickly nation-states.

Indeed, the proper functioning of EU institutions requires that no important constituency (left or right, East or West, and so forth) feels left out. And the new European Commission looks rather strong, given that more than 20 of its 28 members previously served as prime ministers, deputy prime ministers, or ministers. People who have held high political office at home find it worthwhile to come to Brussels.

But most attention has focused on the EU’s three top positions: the President of the European Commission, the President of the European Council, and the High Representative for external affairs.

The Commission’s new president, Jean-Claude Juncker, was the first ever to be selected based on his faction’s strong showing in the European Parliament election. As a seasoned Brussels insider, he was not one to move the crowds. But sometimes this can be an advantage. An insider knows best how to reconcile contrasting interests and how to get the institutional machinery moving again, as Juncker showed with his deft handling of the distribution of tasks among the individual Commissioners.

Selecting the president of the European Council required considerable time and horse-trading, with Polish Prime Minister Donald Tusk emerging as the final choice. But, though Tusk now has an important-sounding position, the European Council President decides nothing. The president mainly presides over the meetings of the EU’s national leaders, and an incumbent’s influence depends on his or her ability to set the agenda and facilitate compromises.

The experience of the previous incumbent, former Belgian Prime Minister Herman van Rompuy, in dealing with his own country’s fractious coalitions proved very useful when he had to persuade national leaders to make decisions during the euro crisis. Tusk will have to achieve something similar in the face of the new challenges confronting Europe today, which include Russian aggression in Ukraine, the rise of terrorism in the Middle East, and a stagnant economy at home.

On the EU’s most immediate challenge, posed by Russia, Tusk will have to broker decisions with leaders from countries that feel immediately threatened (like his own) and those for which economic ties with Russia outweigh any threat to European security, which they feel to be remote. On the economy, he must reconcile the priorities of full-employment Germany with those of Greece and Italy, which remain in the grip of recession and sky-high unemployment.

Being able to converse directly with the Council’s members, mostly in English, might be the biggest immediate challenge, as he admitted immediately.

The appointment of the Italian foreign minister, Federica Mogherini, as High Representative of the Union for Foreign Affairs and Security Policy has been widely questioned, owing to her limited executive experience in foreign policy. But, since the de facto invasion of Ukraine in late August, her government has changed its position on Russia, and she has sought to convince many critics that she knows the problems facing Europe well (her university thesis, for example, was about political Islam).

But can she lead? Europe’s foreign service, the European External Action Service (EEAS), is a huge bureaucracy, which must be managed well if it is to be effective. And, though the head of the EEAS has been dubbed the "EU’s foreign-policy chief,” Mogherini should be seen as its CEO, with key decisions taken by the member states’ leaders when they convene in the European Council. Her lack of managerial experience is thus her key weakness, and she will have to find a strong team to support her.

But there is at least one encouraging, if hidden, signal from Mogherini’s appointment: The fact that the European Central Bank President Mario Draghi is also an Italian was not an impediment. This implies that the ECB presidency is not counted among the posts to be distributed according to nationality quotas, and that Draghi’s nationality is not regarded as having influenced his decisions in any way.

Leaders of the EU’s institutions have to be political entrepreneurs if they are to leave a mark on history. Their decision-making power is limited. But they can often frame the choices and broker coalitions to push the existing boundaries of European integration. None of the EU’s top three new faces (Juncker, Tusk, and Mogherini) has a track record in this sense. Evidently the national bosses like it that way.

Daniel Gros is Director of the Center for European Policy Studies.Copyright: Project Syndicate, 2014.www.project-syndicate.org