There is growing consensus on Capitol Hill and at the White House that any deal to fund foreign wars, and possibly the entire government, must include significant new measures to address the U.S.-Mexico border, but Republicans and Democrats are deeply split over what changes to make.President Joe Biden and Democrats in Congress, who had previously resisted the idea of tougher immigration policies as a price for a spending deal, have pivoted in recent weeks and are now considering concessions as part of an emergency bill to provide aid to Israel and Ukraine. And Republicans, who have been agitating for months for strict new border measures, are demanding a host of policy changes, including an overhaul of asylum laws.

The discussion, taking place before a government funding deadline in just over a week, reflects how fraught the politics of immigration have become for Biden and Democrats. The party’s liberal base, which opposes most of the stricter GOP-backed initiatives, was already angry at the president for embracing some of the Donald Trump-era measures he campaigned against, such as border wall construction. But polls have also shown deep dissatisfaction with how the Biden administration has handled a recent surge in migrants, and many Democrats fear a voter backlash if they do not accept at least modest changes.

“I’d like to bridge the divide,” Sen. Chuck Schumer, D-N.Y., the majority leader, said Tuesday on the Senate floor. “Our caucus would like to see some kind of common-sense border policies done, and the president would like to get something done. “ But,” he added later, “Republicans need to actually work with us on realistic border policies.” Sen. Mitch McConnell, R-Ky., the minority leader, said he told Biden and Janet Yellen, the Treasury secretary, on Monday that “it would be difficult to get the package across the floor of the Senate without a credible border solution.”Senate Republicans have proposed a border plan that largely mirrors a severely restrictive bill that Republicans pushed through the House in the spring over unanimous Democratic opposition. It would reinstitute Trump-era policies requiring migrant families to be detained at the border and forcing people who cannot be housed in detention facilities to wait outside the country until their cases are processed.

The proposal would also make it more difficult for migrants to apply for asylum, which is designed to allow people fleeing persecution or violence in their home countries to seek refuge in the United States. Republicans are pressing to raise the bar for migrants to claim a “credible fear of persecution"—the legal standard for an asylum application—so that they would have to show that their persecution was “more likely than not” if they returned home, instead of the current requirement that they believe persecution is a “significant possibility” if they were to be sent back.