Republicans and some Democrats want more arrests, detentions and deportations to deal with the historic numbers of migrants illegally crossing the southern border. But agencies doing that work don't have enough cash as it is, sources tell Axios.

Why it matters: Stalled funding deals in Congress are threatening to make an already chaotic situation along the U.S.-Mexico border even worse, as lawmakers demand action but can't agree on a plan to pay for it.

• Border money is tied up in raging political debates over immigration, government spending and military aid to Ukraine.
• Republicans are calling for President Biden to do more to secure the border — even as they reject spending requests and policies they say don't go far enough.
• If the standoff continues, "we're going to have to make tough business decisions on what we're going to cease and significantly slow down," one DHS official, who spoke on the condition of anonymity, told Axios.

Driving the news: "We must insist that the border be the top priority," House Speaker Mike Johnson (R-La.) said after a meeting with the White House and congressional leaders on Wednesday.

• A bipartisan group of senators has been hashing out a deal on border policy for weeks, while Johnson and conservatives in the House have largely insisted on their sweeping, GOP-only border bill.
• Congress also looks likely to push back the deadline for passing new funding for the government, including DHS, once again.

Zoom in: Immigration and Customs Enforcement (ICE) is hundreds of millions of dollars in the hole, Axios has learned. DHS also had to reshuffle funds last year to fill gaps.

• ICE has been pulled in to help its sister border agency, and has more migrants in its detention centers than initially given money for.
• It has also spent more money on deportation flights and ramped up a controversial program to fast-track migrant family removals.
• Without a significant influx of funds soon, at least one of those priorities will have to give. That could worsen an already chronically backlogged immigration system.

Customs and Border Protection (CBP) has had to pay massive amount of money to keep temporary processing facilities running along the border and increase migrant transportation.

• They are now slated to give their agents a pay raise and overtime.
• "If we don't put in more money, they have to take it out of somewhere," said Rep. Henry Cuellar (D-Tex.) who represents a border district and sits on the appropriations committee. "And that somewhere is the operational budget."
• Top agency officials are already planning for worst-case scenarios, sources tell Axios.

What they're saying: In the absence of supplemental money, immigration agencies will likely have to make painful cuts in their day-to-day work.

• "Congress' inaction only exacerbates the infirmities of an immigration system that has been broken for decades," a DHS spokesperson told Axios in a statement.
• Meanwhile, the wave of desperate people taking long journeys to the border for a chance at a new life in the U.S. shows no signs of slowing.