The United States long resettled more refugees a year than every other country combined. That gave us global leverage. American leadership helped increase the number of countries formally admitting refugees to a record 37 in 2016, from 14 in 2005. That same year, the Obama administration rallied other nations to double admissions worldwide.

The Trump administration’s abdication of responsibility has contributed to a 48 percent drop in global resettlement from 2016 to 2017. Data from the United Nations Refugee Agency forecasts an even steeper decline this year. As Filippo Grandi, the United Nations high commissioner for refugees, put it, if the American share of refugee resettlement diminishes, “my humanitarian negotiating power diminishes as well.”

Last year, Mr. Trump tried to justify a retreat on refugees by suggesting that American assistance alone is sufficient. But the administration also sought to slash humanitarian aid by 44 percent in its first budget and by 32 percent in its second.

In August, the administration canceled $230 million for Syrian stabilization and all funding for the United Nations agency that assists Palestinian refugees. Diplomacy, resettlement and assistance work together — cutting off one bleeds the effectiveness of the others.

The refugee program also helps us keep faith with key partners, making it more likely they will step up when we need them. In Iraq and Afghanistan, our soldiers, diplomats and aid workers rely on local translators and guides who put their lives on the line to serve by our side. The Trump administration is making a mockery of a special admissions program the Congress established to fast-track their resettlement. So far this fiscal year, between October and August, we have admitted just 48 Iraqi partners, compared with 5,100 in 2016 and 3,000 in 2017.

Some countries of first refuge — like Jordan, Turkey and Kenya — have been counterterrorism partners and hosts to the United States military. These and other countries offering temporary havens are under growing domestic pressure to send back refugees, which risks setting off new humanitarian crises and further destabilizing countries where terrorists find sanctuary.

When we worked at the State Department, we met two young Muslim brothers from Afghanistan who had fled the Taliban. We listened to their story in the California offices of Catholic Charities. They had been resettled by Jewish Family and Community Services, and first found shelter at the San Damiano Friary, a Franciscan retreat.