Cavour's decision no longer to be a virtually passive spectator of the revolution was to destroy Garibaldi's occasional hopes that the northern government might connive in his plan to create an immediate diversion on Papal territory. Cavour wanted no movement in the Papal States, at all events not unless Napoleon gave him permission, nor until he could feel more confident about the success of his agents provocateurs at Naples. He acted only just in time to stop what was happening, for Bertani had begun to mobilize his men, and Garibaldi had written on 30 July with orders to launch the expedition at once. Luckily for Cavour, the dictator's letter took a fortnight to reach its destination, and by the time it arrived the government had been able to defeat the Genoese radicals and break up their army.

What happened was this. On 31 July Farini, the minister of the interior, had hurried to Genoa to see if, in a private talk with Bertani, he could dissuade the radicals without using force. This called for a little mild deceit. Bertani was told that the government had at last decided to intervene openly in aid of Garibaldi, and that the revolutionary committee had better ship their volunteers to Sicily so that France should not be provoked into vetoing what was afoot. After various threats and promises had been made, Bertani was given one day to think the matter over, and on 2 August he agreed to go quietly.