Short answer. If the three justices cannot reach a unanimous vote, Rule 51, Section 3 requires the case to be referred to the Presiding Justice, who designates two more justices by raffle to form a special division of five. A judgment or final resolution then requires only the concurrence of a majority of that five-member division.
What the law says
The participation of all three Justices of a division shall be necessary at the deliberation and the unanimous vote of the three Justices shall be required for the pronouncement of a judgment or final resolution.
Rule 51, Section 3 — Quorum and voting in the court. Read the full provision →
What the law says
If the three Justices do not reach a unanimous vote, the clerk shall enter the votes of the dissenting Justices in the record.
Rule 51, Section 3 — Quorum and voting in the court. Read the full provision →
What the law says
Thereafter, the Chairman of the division shall refer the case, together with the minutes of the deliberation, to the Presiding Justice who shall designate two Justices chosen by raffle from among all the other members of the court to sit temporarily with them, forming a special division of five Justices.
Rule 51, Section 3 — Quorum and voting in the court. Read the full provision →
What the law says
the concurrence of a majority of such division shall be required for the pronouncement of a judgment or final resolution
Rule 51, Section 3 — Quorum and voting in the court. Read the full provision →
The default: three justices deciding unanimously
Section 3 sets a strict starting requirement: the participation of all three Justices of a division shall be necessary at the deliberation and the unanimous vote of the three Justices shall be required for the pronouncement of a judgment or final resolution. Nothing short of all three agreeing is enough to produce a judgment or final resolution at that stage.
What happens the moment they cannot agree
The rule anticipates exactly the situation you are describing: if the three Justices do not reach a unanimous vote, the clerk shall enter the votes of the dissenting Justices in the record. That disagreement is not simply absorbed into a majority outcome within the original three; it is formally recorded and triggers the next step in the process described in the rest of the section.
A special division of five is formed by raffle
Section 3 then describes how the case moves forward: thereafter, the Chairman of the division shall refer the case, together with the minutes of the deliberation, to the Presiding Justice who shall designate two Justices chosen by raffle from among all the other members of the court to sit temporarily with them, forming a special division of five Justices. The original three justices remain part of the case, joined by two more chosen by raffle rather than by selection.
The five-member division decides by majority, not unanimity
Once the special division is formed, the voting standard changes: the concurrence of a majority of such division shall be required for the pronouncement of a judgment or final resolution. So your case is not left unresolved by the original disagreement; it moves to a five-justice division where a majority, rather than unanimous agreement among three, decides the outcome, breaking the deadlock the first division could not resolve.