A majority of the unaccompanied Central American youths rushing into the United States have parents already here and know that federal authorities are legally required to unite the families, according to an immigration expert.

Marc Rosenblum, deputy director of the immigration policy program at the Migration Policy Institute, said having parents and other relatives who had made it into the United States was a “pull factor” in their journey north, now in record-breaking numbers.

“The main pull in the United States is that most of these kids who are arriving have families here,” Rosenblum said in a conference call to discuss the new border crisis. “Between a half and three-quarters of the unauthorized children who are arriving mention having parents in the U.S. as a factor in their migration decision. And 85 to 90 percent of them are being placed with parents or extended family members here while they wait for a removal hearing,” he added.

Rosenblum, a former congressional immigration expert to advised the late Sen. Edward Kennedy, also said that 40 percent to 60 percent of the 52,000 youths who've been apprehended at the border since October have a “valid” humanitarian claim against returning to their country, typically Honduras, Guatemala or El Salvador.

While the rest could be returned to their country of origin, he said President Obama should set a new policy that gives the youths “due process” in the legal system so that they aren't sent back.

Asked later by Secrets if the parents are also in the United States illegally, Rosenblum said, "We don’t know specifics, but more than half of people in U.S. from those countries are unauthorized, and most of the rest have Temporary Protected Status, which does not permit them to petition for their families. In some of these cases, parents may have come on their own to work, and now kids want to join them, including because they are fleeing bad conditions."

In the media call set up by the Woodrow Wilson Center's Latin American Program, Rosenblum said that a 2008 law requiring U.S. authorities to unite families of illegal immigrants is “probably incentivizing or at least contributing to people's decisions to come because in practice what happens is is that when kids arrive, they are placed with their family member while they have those long waits for hearings.”

Due to a court backlog, immigration hearings can be delayed three years. The House Judiciary Committee chairman last week said that at least 90 percent of those ordered to appear at immigration and removal hearings never show up.

On the call, two other experts said that deporting the youths isn’t feasible because Honduras, Guatemala and El Salvador aren’t prepared to resettle the illegals.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.