From flashpoints around the world - wars in Africa and the Middle East, terrorism in Asia, gang violence in Central America - tens of millions of migrants have run for their lives in just the past few years, creating crises of epic scale for many destination nations.
A small fraction, about 85,000 annually, find a haven in the United States as refugees. Last year, 2,645 were resettled in Pennsylvania, including 510 in Philadelphia. New Jersey became home to 314, 91 of whom moved to the Camden area.
Overall, 40 percent of recent refugees are minors. Many have limited schooling, if any. Many speak little English, if any. And so they can find themselves in another, increasingly troubled place: the intersection of immigration and public education.
Experts say school is invaluable for integrating children into American life. The same experts concede the difficulties, particularly with older youth.
For instance, what should a school district - legally obligated to educate students until age 21 - do with a foreign-born 19-year-old who reads at a fifth-grade level?
That question, among others no less contentious, is being argued in a closely watched legal case pitting the School District of Lancaster against six refugee students.
The district maintains it has final say over student placement, including putting the plaintiffs in an alternative school for special instruction.
Barred from attending the regular high school, the teens claim their right to equal treatment under the federal Equal Education Opportunities Act is being denied.
The Lancaster schools lost round one last month, when a district judge ruled the students could attend the city's main high school, 2,600-student J.P. McCaskey.
The intensifying battle has since made its way to the U.S. Court of Appeals for the Third Circuit.
Allegations that older refugee children have been systematically denied enrollment in public schools, or funneled to inferior alternative programs, have been leveled in cases in Collier County, Fla., and more than 20 districts in New York State. In March, the New York Attorney General announced a partial settlement with Utica, which will begin outreach in five languages to let refugees know they have the right to attend school.
The cases foreshadow litigation likely to arise in more districts, given the Obama administration's recent decision to admit 110,000 refugees in fiscal 2017, up from the current cap of 85,000.
Issa v. School District of Lancaster had its first hearing last month in an Easton courtroom, where 17-year-old Khadidja Issa, draped in a powder blue hijab, testified through an Arabic interpreter.
Born in Sudan, she was 5 when war and famine forced her family to flee to Chad. She completed only sixth grade.
Admitted to the U.S. last year, the family settled in Lancaster, and Issa tried to enroll in McCaskey. District personnel, she testified, told her she was "too old" and "under-credited" to earn a diploma before aging-out at 21.
"Get a job," she said administrators advised her.
"Why would I want a job if I don't have an education?" she said she replied.
When Issa persisted, the district steered her to Phoenix Academy, a for-profit, 325-pupil "accelerated credit recovery school" in Lancaster, under contract to the district.
A spokesman for Camelot Education, the Texas-based firm that owns Phoenix, said the Lancaster district pays the academy $11,178 a year for each student it sends there - $520 less than its per-pupil spending at McCaskey.
Schools such as Phoenix exist to help under-credited students catch up fast. Indeed, Issa testified that her English classes moved so swiftly, she was left breathlessly behind. Phoenix, she said, is "inferior" to McCaskey's recognized excellence in programming for English learners.
The district has argued that Phoenix, also known for its behavior modification programs, is the proper placement for Issa and students who fit her profile, because it gives them the best shot at an all-important diploma quickly.
Since Phoenix's first year, 2011-12, it has graduated 40 refugee students, according to executive director Megan Mirsik.
Its students get "more focused instruction, away from the distractions" of the large high school, said Sharon O'Donnell, lawyer for the district. Phoenix, she added, "is not the prison some people make it out to be."
To Issa, though, Phoenix felt like a "disciplinary" environment. Each day, she said, began with a "pat down" frisk of students, who were barred from carrying book bags or feminine hygiene products.
Co-plaintiff Qasin Hassan, 17, stopped attending. He told the court why.
He was 12, he said, when his father was killed by jihadists in Somalia and the family fled to Egypt. He didn't attend school, but he taught himself Arabic. When he learned he'd be coming here, he was ecstatic, he said, because "USA - number one."
However, he grew disillusioned at Phoenix, he said, because it had no Arabic or Somali interpreter, and never dialed a language helpline for an assist.
Worse, he said, he was taunted by students who said things he didn't understand. When he used the bathroom, bullies kicked the stall and ran away.
Isolating "interrupted learners" in an outside program can feel like punishment, Betsy Rymes, chair of educational linguistics at the University of Pennsylvania Graduate School of Education, said in an interview.
"It's better for the kids not to be segregated in terms of their learning opportunities, [and] better for the community," she said. "If we are going to be a global society, you can't just take people and separate them out and pretend they are not there."
In the Philadelphia School District, refugee students up to age 21 are offered regular admission, said Allison Still, deputy chief of the Office of Multilingual Curriculum and Programs.
About 13,000 of the district's 130,000 students are identified as English language learners (ELL) needing special support. How many are refugees, she said, she did not know.
Depending on their prior education and responses to a home language survey, refugee students in Philadelphia can choose: attend the Newcomer Learning Academy - an intensive program for about 80 students a year at Franklin Learning Center in Spring Garden - or take ELL classes at their regular high school.
"It's a challenging situation, especially when students are older," Still said. "What they really need is time, which is exactly what they don't have."
If they age-out before they graduate, they can apply their credits to a GED.
On Aug. 26, the Lancaster students - represented by the ACLU of Pennsylvania, pro bono counsel from Pepper Hamilton LLP, and the nonprofit Education Law Center - won their case before Judge Edward G. Smith.
They "are not seeking . . . a new entitlement," he wrote. They want admission to "a program that currently exists [and] is specifically designed for . . . their unique language needs."
One of the six had graduated. One did not register for school. Four enrolled at McCaskey on Aug. 30.
That day, the district announced it would appeal the ruling to prevent "trial judges from substituting their judgment for that of the school board when placing children in educational settings."
The appeals panel is expected to consider the case sometime within the next month.
Editor's note: This story was revised to correct the number of students at McCaskey High School.