In the wee hours of Friday morning, leaders of the member states of the European Union announced they had reached an agreement at the European Council meeting on the contentious issue of migration.

The agreement includes important measures seeking to stem migration at its source; however, the devil will be in the details.

How countries interpret the agreement and to what degree it is implemented remain open questions. The frenzied jockeying over migration at the council meeting exposed deep fault lines between member states, and left many questions unanswered.

The European Council meeting saw the confluence of several political eddies related to migration, the most important of which are the arrival of a new populist government in Italy and the domestic political troubles faced by German Chancellor Angela Merkel.

The council meeting was the first for Italian Prime Minister Giuseppe Conte, who heads a populist coalition government between the Five Star Movement and the Lega party. Both parties campaigned on platforms that promised to address the migrant crisis and its effects on Italian society, and Conte was under political pressure to deliver results.

The central Mediterranean route from North Africa has been the most active migrant route in recent years, placing tremendous strains on Italy, a country that has seen 750,000 migrant arrivals since 2011.

Likewise, Merkel arrived at the meeting under tremendous strain. A battle with Interior Minister Horst Seehofer over migrants left Merkel in need of an agreement to save her coalition government.

Initial indications are that the chancellor is likely to have achieved just enough in the agreement to survive a domestic fight, which nearly proved politically fatal. However, more than likely, continued aftershocks of Merkel’s open-door policy toward migrants will continue to embroil her in politically contentious waters.

The countries agreed to create “regional disembarkation platforms,” holding and processing centers in third-party countries; namely, in North Africa. Migrants rescued outside of the territorial waters of an EU member state will be brought to these centers for their asylum claims to be processed.

The agreement also envisions the creation of “controlled centres set up in Member States.” Migrants rescued within the territorial waters of an EU member state will be brought to these centers to be processed.

Italy’s Conte, whose nation has been at the forefront of seeking to address the issue of migration at the source, said that the agreement shows “Italy is not alone anymore.”

Many migrants, upon reaching Europe, have taken advantage of the Schengen Area (which allows for the free movement of people, goods, services, and capital among 26 EU countries that take part) to travel further northward to France, Germany, Sweden, and elsewhere.

A number of European countries, including Germany, have reintroduced temporary border controls to stem the movement of migrants between countries.

Seeking to safeguard the Schengen Area, which she deems inviolable, Merkel pushed for a statement in the agreement that “member states should take all necessary internal legislative and administrative measures to counter such movements and to closely cooperate amongst each other to that end.”

The statement likely will help her defuse her disagreement over border controls with the interior minister. However, in the end, the degree to which countries carry out this promise is uncertain.

Implementing the agreement, which is light on details, is sure to prove tricky. Controlled centers to be set up in EU member states are to be done “on a voluntary basis,” and thus far, no country has volunteered to host any.

Similarly, which—if any—countries in Africa will host the “regional disembarkation platforms” is another potential glaring shortfall.

The agreement also promises funds for front-line states, such as Italy and Spain, in handling migrant arrivals and calls on EU members to contribute more to the Trust Fund for Africa. Whether either of these calls are heeded is another question left unaddressed.

Finally, the agreement contains two important provisions that at least initially have fallen under the radar. First—in a significant win for Central and Eastern European countries, such as Hungary and Poland, which have rightly rejected the idea of imposing mandatory migrant relocation quotas—relocation of migrants from the so-called “controlled centres” will be on a “voluntary basis.”

Secondly, the agreement contains strong language warning nongovernmental organizations whose boats help “rescue” migrants: “All vessels operating in the Mediterranean must respect the applicable laws and not obstruct operations of the Libyan [coast guard].”

Italy’s interior minister has likened the nongovernmental organizations’ boats to a “taxi service” for migrants, and French President Emmanuel Macron recently criticized the NGOs as “playing into the hands of smugglers by reducing the risks of the journey.”

Efforts to crack down on nongovernmental organizations operating in the Mediterranean are sure to be forthcoming.

One thing’s for certain: Even with today’s European Council agreement, the issue of migration will continue to have a sweeping impact on politics and policy in Europe for years to come.