At the beginning of the war, Austria did not ignore that her loss of territory might exceed Venetia. The Archduke Albrecht, in his proclamation to his soldiers, appealed to them to protect their mothers, wives and sisters from being ruled by a foreign race.
Even a successful raid upon Dalmatia or Istria need not have given those districts to Italy, but it would have brought such an event within the range of a moderately strong political telescope. The Slavs (erected since into a party hostile to their Italian fellow-citizens by a fostering of Panslavism which may not, in the long run, prove sound policy for Austria) were then ready to make friends with anyone opposed to their actual rulers. They would not have been easy to govern after an Italian invasion; still less easy to govern would the Latin element have been, which was and is Italianissimo. Since Prussia became the German Empire, she has set her face against Italian extension eastward, but in 1866, had her advice been intelligently acted upon, it might have generated facts the logic of which none would have had the power to stay.
Moltke’s plan more than hinted at a march on Vienna by the Semmering, and this is what is supposed to have induced La Marmora to treat it with scorn. With the bogey of Prussia vanquished before his eyes, he doubtless asked what the Italians would do at Vienna if they got there? He put the plan in his pocket, and showed it neither to his staff nor to the King, who would certainly have been attracted by it, as he had set his heart on the volunteers, at least, crossing the Adriatic. With regard to the campaign at home, both Moltke and Garibaldi counselled turning the Quadrilateral in preference to a direct attack upon fortresses which had been proved impregnable except with the assistance of hunger, and at present they were better provisioned than in 1848. The turning of the Quadrilateral meant the adoption of a route into Venetia across the Po below Mantua. An objection not without gravity to that route was the unfavourable nature of the ground which, being marshy, is liable after heavy rains to become impassable. But against this disadvantage had to be weighed the advantage of keeping out of the mouse-trap, the fatality of which needed no new demonstration.
In Italy it is common to hear it said that it was necessary to station a large army on the Mincio to bar the Archduke’s path to Milan. But apart from the rumoured existence of a promise to the French Emperor not to invade Lombardy, it was unlikely that so good a general as the Archduke would have taken his small army far from the security it enjoyed among the four fortresses which, if the worst came to the worst, assured him a safe line of retreat.