Where the arbitration clause confers on the president of the court the power to appoint also the arbitrator to be nominated by the party which has failed to do so, the parties’ inaction and the consequent impossibility of constituting the arbitral tribunal satisfy the conditions for the exercise of that substitutive power, which is to be exercised so as to allow the arbitral tribunal to be duly constituted.
The president of the court appoints the arbitrator in substitution for the defaulting party even where the arbitration clause provides for contractual arbitration (arbitrato irrituale).