By Pat Loeb

PHILADELPHIA (CBS) — Child advocates estimate that as many as 20,000 undocumented children in Pennsylvania can’t get health insurance because of their immigration status. Now, they’ve launched an effort to get them included in the state’s CHIP insurance program for children. But they face an uphill climb.

CHIP has been a national model for getting kids insured — but it’s no accident it excludes undocumented kids. Some Pennsylvania legislators feel strongly about the carve out.

“Our government’s responsibility is first and foremost to protect our citizens from being taken advantage of by illegal aliens,” says Representative Daryll Metcalfe.

Metcalfe says he cannot be swayed either by the economic argument — that it’s cheaper to cover kids than to provide costly emergency care when an untreated condition escalates — or by ideological ones.

“We have an obligation to meet the emergency health needs of individuals,” he says, “but we don’t have a moral obligation to meet every health need of someone who is here illegally.”

That sentiment kept undocumented children out of a CHIP expansion in 2007. But Colleen McCauley of Public Citizens for Children and Youth says five states have since opted to include them with good results, and a local coalition hopes that will convince some in Harrisburg.

“It’s good policy,” McCauley says, “and it’s good for our children and families.”