The crush of migrants that overwhelmed U.S. border facilities in the spring, producing appalling conditions for migrant children at Customs and Border Protection stations, has eased with summer's arrival as scorching temperatures and deterrent measures adopted by Mexican authorities drove down border-crossing arrests by nearly a third between May and June. Together with the $4.6 billion in supplemental funding enacted by Congress and signed by President Donald Trump, that is taking pressure off the government's capacity to manage the flow of migrants, especially the families and minors that have transformed the immigration landscape.

What will remain, however, are urgent questions about the Border Patrol, and the degree to which the agency's failings of culture exacerbated a shocking humanitarian crisis on the southwest frontier. If crisis exposes character, then the agency manning the frontlines of America's border with Mexico needs to take a hard look at its own shortcomings - not only of resources but also of professionalism.

Without doubt, thousands of Border Patrol agents have struggled to contend with the biggest spike in migrant border-crossing in more than a decade, and many went the extra mile - playing with children in their care and displaying a hundred other kindnesses. Much of the apparently inhumane treatment of some migrants was reported by Border Patrol agents themselves to watchdog groups and higher-ups in the agency. Homeland Security officials have added additional medical personnel and opened new facilities to accommodate minors.

Still, the accounts of visitors to the Border Patrol's station at Clint, in far west Texas, and reporting on the same facility by the New York Times, strongly suggest that Border Patrol officials failed to respond to warnings of filthy, unhygienic and dangerous conditions for unaccompanied minors there. True, it was a shortage of bed space that produced a bottleneck in which hundreds of migrant children were stuck in facilities such as the one in Clint, originally built to hold adults. But the fact that those children, some of them infested with lice, were forced to endure weeks at the station without clean clothing, soap, toothpaste and other basic necessities - even as the Border Patrol sector chief for that region, Aaron Hull, insisted that the agency had maintained humane conditions - is a sign of institutional indifference and callousness.

That impression is reinforced by reports of private Facebook group pages linked to current and former CBP agents that feature obnoxious, sneering and obscene references to undocumented migrants and Hispanic members of Congress. Border Patrol and Homeland Security officials insist the pages and commentary are unacceptable and unrepresentative; they have ordered investigations and taken disciplinary action against some personnel.

It's anyone's guess how deeply infected the Border Patrol has become by the toxic attitudes reflected in those Facebook groups. What's worrying is that the intolerance and contempt for migrants afoot within the agency have only been encouraged by Trump, whose constant disparagement of migrants is a hallmark of his rhetoric. Little wonder it has found echoes in the far bureaucratic reaches of his administration.