be for all the marbles

To be the deciding factor in determining who wins total victory or the entirety of a prize or reward. Typically said when one is on the verge of victory. He is just barely holding on to first place, so this final putt is for all the marbles! The remaining poker players have gone all in, so this last hand is for all the marbles—nearly $250,000 in prize money. This run is for all the marbles—can she surpass the Swede's time down the slopes and capture the gold medal?