Английский словарь американских идиом - back to the wall

or back against the wall {adv. phr.} In a trap, with no way to escape; in bad trouble. * /The soldiers had their backs to the wall./ * /He was in debt and could not get any help; his back was against the wall./ * /The team had their backs to the wall in the second half./ Compare: BETWEEN THE DEVIL AND THE DEEP BLUE SEA, LAST DITCH, ON THE SPOT, UP AGAINST IT.