With summer’s warmer weather and calmer seas, tens of thousands of desperate migrants are setting out for Europe from Libya, once again overwhelming the capacity of rescue efforts on the Mediterranean and straining the ability of Italy to cope. Between Jan. 1 and June 21, some 72,000 migrants arrived in Italy from Libya. More than 2,000 other people died while on the way.

The conditions in Africa — deadly conflicts, despotic rulers and extreme poverty — that send people across the Sahara and into the chaos of Libya are only getting worse. In Libya, human traffickers await to enslave, beat, torture and rape the migrants before sending them out to sea. It would be unconscionable for the United States to cut humanitarian aid to Africa now, as the Trump administration is threatening.

Meanwhile, Italy has effectively been turned into a holding pen for migrants by the European Union’s Dublin Regulation, which requires asylum seekers to file their claims and await the outcome in the European country where they first arrive. Fewer than 21,000 of the 160,000 people already in Italy and Greece whom other European Union nations agreed to take in 2015 have been relocated. Hungary, Poland and the Czech Republic are flatly refusing to participate, despite a threat of fines.

People who try to push on from Italy into France face police officers wielding tear gas at the border. Those who do make it across find a country unprepared for their arrival: Nearly 1,200 are now sleeping on bare ground in the neighborhood of La Chapelle on the northern edge of Paris, where temporary shelters for migrants are full. Hundreds of others, intent on reaching Britain, live in squalor in Calais, where the infamous migrant camp known as “the Jungle” was razed last year.