GENEVA — The Hungarian government announced plans earlier this month to build a 175-kilometer-long, four-meter-tall barrier along its border with Serbia. Ostensibly for protection, the project is yet another barricade built at the edges of the European Union , where the foundations of the borderless Schengen Area are weakening by the day.

Faced with the growing difficulty of leaving Greece by sea or air, migrants are choosing the long land route through the Balkan peninsula to reach the Schengen Area. As we near its 30th anniversary, tensions between member states are intensifying. In France , Austria and Switzerland, the specter of closing borders to keep out migrants is rearing its ugly head.

A quarter-century after the fall of the Iron Curtain , Hungary wants to rebuild a physical frontier with Serbia, this time to block access to the EU for thousands of northward-bound asylum seekers. Hungarian Foreign Minister Peter Szijjarto declared that his government would launch technical and diplomatic preparations for the erection of a fence spanning the Serb-Hungarian border between the Hungarian cities of Mohacs and Szeged. (Late Monday, Hungary's parliament approved the plans for the giant barrier.)

The border is one of the last open land routes left in the peninsula, where refugees fleeing the Middle East wars and southern Europe's failing economies make their way through Greece, Bulgaria, Macedonia, Kosovo and Serbia to reach the holy grail of Schengen. EU border surveillance agency Frontex reported 43,360 illegal border crossings in the Balkans in 2014, up from 6,400 in 2012. An alarming 50,000 have been recorded since January of this year, half from Kosovo alone.

With a population of just under 10 million, Hungary is finding itself on another frontline of the EU's burgeoning humanitarian crisis . The number of asylum seekers in Hungary grew to over 50,000 last year, a figure already surpassed in the first half of 2015.

"The EU is still looking for a solution, but Hungary can't keep waiting anymore," says Szijjarto. He notes that Budapest isn't violating any international agreements and that there is ample precedent for similar barriers to guard against illegal immigration.

"I'm shocked and surprised," Serbian Prime Minister Aleksandar Vucic says of the Hungarian plan. He resents Budapest's decision not to consult Belgrade before opting to build the fence. "We count on discussing these issues with our partners in the EU," Vukic says. Hungary was among the countries most hostile to the European Commission's proposal to distribute 40,000 refugees currently in Greece and Italy among the bloc's 28 members.

Walls are futile

Seeking to counter the rising popularity of the extreme-right Jobbik party , the government of Hungarian Prime Minister Viktor Orban recently released a controversial survey to its citizens that associated immigration with terrorism . Budapest also used public funds to embark on an extensive poster campaign to promote the survey, a move that attracted criticism from the European parliament. The United Nations High Commissioner for Refugees (UNHCR) responded with its own campaign highlighting Hungary's ability to absorb asylum seekers and the economic benefits of their integration.

"Walls have never been useful, and they're easy to get around," says Yves Pascouau of the Jacques Delors Institute. In Greece, the flood of migrants that used to cross the Evros river along the Turkish border has stopped since Athens constructed a barricade. But the refugees set their sights elsewhere and the influx resumed, this time on the Greek isles closest to the Turkish coast, where they continue their arduous journey through the Balkans.

Further to the west, Italy has been enduring a considerable inflow of refugees for the past two years. Rome is increasingly on a collision course with its neighbors in France, Austria and Switzerland, who are growing increasingly tempted to close their borders with Italy to incoming migrants. Hundreds of refugees are stranded at the Franco-Italian border near Ventimiglia, putting strain on the countries' relations.

"What's happening in Ventimiglia evokes the events of 2011, when the diplomatic spat between France and Italy led to a modification of the Schengen agreement that allowed for the provisional re-establishment of border controls," Pascouau explains. "This has to relate to specific criteria, such as the disruption of public order, and I'm not sure that this condition has been satisfied this time around. But I also don't think the European Commission will request the European Court of Justice to rule if France's actions violated EU rules."

French Interior Minister Bernard Cazeneuve notes that France didn't close the border. "People are still crossing it," he says. "Actually, we are sending people back to Italy, which is legal under European law." He cites the Dublin Regulation, which requires asylum seekers to remain in the first European country in which they arrive, a heavy burden primarily shouldered by Italy and Greece.

Austria announced on June 13 that it would suspend all asylum requests and begin placing border controls along its frontier with Italy. Switzerland, which isn't an EU member but is part of the Schengen Area, is similarly alarmed by the migrant crisis. Three days after the Austrian announcement, the Swiss declared that the number of refugees crossing into the alpine nation from Italy was "exceptionally high." Over the course of just two days, 350 people entered the country from the Chiasso crossing, causing a bottleneck at the border.

Switzerland isn't equipped for the growing tide of "claimants," as Bern calls them. In 2014, 23,765 people submitted asylum requests in a country with fewer than 2,000 places in its official refugee centers. Almost half of the requests came from people in the Italian-speaking part of the country, in the canton of Ticino. The government planned to build 5,000 extra rooms for refugees but ran into fierce opposition from the cantons.

Enough is enough

To deal with the influx, Swiss authorities have imposed a hierarchical system to prioritize certain asylum requests over others. Consideration of requests from Eritrean refugees, who comprise the vast majority of new arrivals , has been suspended. Due to the urgency of the situation, the state secretary for migration increased the number of beds available in "public shelters," or bunkers. Generally located underground, the bunkers have been around since a 1963 law mandated their construction for every new building to protect people in case of an emergency. The decision to house the migrants in the shelters sparked demonstrations by the left, with protesters brandishing the slogan "no bunkers, no deportation."

According to the Swiss People's Party, the country's largest, "enough is enough." The populist outfit is demanding the suspension of the asylum law for at least a year. With parliament currently debating a bill that would expedite the application process for refugees, it remains to be seen which direction Switzerland, and Europe, will take.