President Biden and Democrats on Capitol Hill are seriously considering Republican demands for deeply restrictive immigration policies in exchange for billions of dollars in aid for Ukraine, a move that activists say would devastate America’s obligations to welcome desperate migrants fleeing war and oppression.

Mr. Biden has said he is willing to make “significant compromises” on border security to satisfy Republicans, who will not support any more aid for Ukraine without a new crackdown on immigration.

Republicans last week blocked a $111 billion emergency spending bill, which includes about $50 billion in security assistance to Ukraine, and made a counteroffer that amounted to a Trump-era wish list for the border.

Mr. Biden has accused Republicans of holding military aid to Ukraine hostage in exchange for “an extreme Republican partisan agenda on the border.”

Here’s a look at the state of the negotiations:

What Republicans Want

Republicans have said they want to make it more difficult to gain asylum in the United States — a demand that the White House has signaled it is willing to consider.

But Republicans say that is not enough.

They also want to restore policies that would either rapidly turn people away at the border or force them to wait in Mexico until their asylum case is heard. Former President Donald J. Trump used those methods to effectively shut the border to migrants during his administration.