US president Barack Obama and Republican leaders will meet tomorrow with $85 billion (£56bn) in automatic spending cuts set to kick in.
The talks are so last-minute that any breakthrough on averting the painful measures is virtually impossible.
The cumbersome annual ritual of passing agency spending Bills collapsed entirely last year and Congress must now act to prevent the partial shutdown.
The automatic spending cuts could inflict major damage to government programmes and the military. Republicans are planning a Bill to fund day-to-day government operations.
Their plan would award the Pentagon its budgets for a more targeted batch of military cuts but deny domestic agencies the same, which has whipped up opposition from Democratic senators.
Domestic agencies would see their budgets frozen almost as they are, meaning no money for new initiatives such as low-income housing programmes.