The fear among immigration advocates is not only that thousands of refugees could remain stuck in overseas camps. Or that staffers at resettlement agencies in Philadelphia and elsewhere could be laid off or reassigned.

With President Trump expected to again lower the annual limit on refugee admissions, advocates are afraid that the United States' historic mission of welcoming the world's most vulnerable people could effectively be coming to an end.

The talk filtering from Washington to on-the-ground agencies is that Trump could put the new cap at 25,000, with perhaps only half that number actually entering the country, the result of bureaucratic delays and other factors. He set the current year's figure at 45,000, a nearly four-decade low. Less than half that number have been admitted as the end of the fiscal year approaches on Sept. 30.

"It's really sad," said Peter Gottemoller, director of Pennsylvania refugee programs for Bethany Christian Services. "Our administration has decided our role in the world shouldn't be what it's been."

In Philadelphia, Bethany expected 100 refugees this year, but so far has received only 31. In Allentown, the agency was ready for 100, but resettled 41.

The Nationalities Service Center, known as the largest, most comprehensive immigrant-service provider in the region, might settle 95 refugees during the entire fiscal year. In an earlier, busier time, it resettled that many in a single month.

"For me, it's changing who we are as a country," said Margaret O'Sullivan, executive director of NSC. "Are we going to be the [generation] that closes the door?"

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By law, the president, in consultation with Congress, must issue what is called the Presidential Determination before the new fiscal year starts  Oct. 1. Generally, the number begins to leak from government officials around Labor Day.

The demand for help has rarely been greater, as the world experiences its worst refugee crisis since World War II. An estimated 25.4 million people have been forced from their homelands by war, genocide, persecution, or natural disaster, according to the United Nations. At the same time, the U.S. is led by a president who warns that the nation has lost control of its borders, who banned entry from several Muslim-majority countries, and who wants to build a wall along the Mexican border.

Refugees differ from some other migrants in that they carry a specific legal status. If chosen for resettlement in the U.S., they undergo extensive vetting and security checks that can take up to two years.

The 45,000 cap represents the lowest figure since 1980, when Congress created the current refugee program through the U.S. Refugee Act, and is less than half of the 110,000 set by President Barack Obama in 2016.

Not all of those 45,000 spaces will be filled. Advocates blame a bureaucratic slowdown, though the imposition of additional vetting measures also caused a lag.

Through July 31, only 18,214 people had been admitted to this country, according to State Department figures. That pace equates to about 22,000 for the year.

And many people would approve.

Forty-three percent of Americans believe the U.S. has no responsibility to accept refugees, according to a Pew Research Center survey conducted in April and May. Fifty-one percent say it does.

The Federation for American Immigration Reform, which seeks to reduce overall immigration, says that the U.S. has a moral obligation to help — but that bringing refugees here is the most expensive option and helps the fewest. The government should focus on helping displaced people take temporary shelter close to their home nations, the group says.

>>READ MORE: History repeats: When America turned away refugees

Now the White House is considering a second sharp reduction in the number of refugees, and under one plan would allow no more than 25,000 to come here, the New York Times reported. Last year, presidential adviser Stephen Miller advocated for a limit as low as 15,000, and chief of staff John Kelly said that if it were up to him, the number of refugees admitted to the U.S. would be between zero and one, the newspaper reported.

Historically, the U.S. has led the world in resettlement, and since 1980 has taken in three million of the more than four million refugees who have moved to new homes in new nations worldwide, according to the Pew Research Center. But in 2017, for the first time since 1980, the U.S. resettled fewer refugees than the rest of the world, taking in 33,000 compared with the 69,000 accepted by other nations combined, Pew found.

Refugees come to the Philadelphia region from Afghanistan, Iraq, Bhutan, and elsewhere around the globe, but now in smaller numbers.

"We can't just be quiet about this," said Cathryn Miller-Wilson, executive director of HIAS PA, which provides legal and support services to immigrants, refugees, and asylum-seekers. "Those kind of numbers are the elimination of the refugee resettlement program."