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.