By Richard Cowan

WASHINGTON (Reuters) – The U.S. Congress left Washington this week for an extended holiday break with several key issues unsettled including emergency aid for Ukraine and tighter border security, setting the stage for a complicated January.

Lawmakers will face two government-shutdown deadlines and continue efforts to write one piece of legislation that will both fund Ukraine’s defense against Russia and slow the flow of migrants through the U.S.-Mexico border. Meanwhile, Republican voters will begin to choose their nominee to challenge Democratic President Joe Biden in the 2024 election.

“We will hit the ground running,” Democratic Senate Majority Leader Chuck Schumer said of Congress’ return the week of Jan. 8.

Biden has urged Congress to approve an additional $61 billion in new support for Ukraine’s war effort, which conservative Republicans have demanded be paired with stronger border security laws at a time of record immigrant arrivals.

House of Representatives Speaker Mike Johnson and his fellow Republicans have been hammering Biden over border control, an issue U.S. voters are increasingly restless over.

Congress also has deadlines of Jan. 19 and Feb. 2 for funding U.S. government programs. Failure to reach deals on 12 spending bills, following a full year of deficit-reduction battles, would bring widespread government shutdowns.

Bipartisan Senate negotiations are also continuing over the recess with the aim of producing a deal on reforming antiquated U.S. asylum laws. That would open the door to Senate votes to help Ukraine and send U.S. aid to Israel for its war against Hamas in Gaza and to Taiwan.

Just before leaving town on Wednesday, Republican Senate Minority Leader Mitch McConnell echoed Schumer’s urgency, saying in a speech that the unusual combination of U.S. immigration reforms and foreign military aid were urgently needed “from South Texas to Southeast Asia and to the Red Sea.”

Both Schumer and McConnell acknowledged that passing the first major immigration revisions in four decades is arduous. But so is simply approving around $1.5 trillion to keep a bunch of regular government programs operating.

Without action, many agriculture and nutrition programs will run out of funding on Jan. 19, along with money for airports, highways and federal housing programs and for building military facilities and maintaining veterans’ aid.

There also are plenty of fights over the funding and policies of the Justice Department and social safety net programs administered by Health and Human Services. These too face a Feb. 2 deadline and can be among the toughest annual appropriations bills to pass in Congress.

(Reporting by Richard Cowan; Editing by David Gregorio)