As results came in from elections in 160 communities, it became clear the League's antics had made a negative impression. Mr Bossi's party came in a poor third in the key northern cities - Mantua, Pavia and Lodi - where League candidates were running for mayor.
Instead, candidates from the governing centre-left Olive Tree alliance led in all three cities and seemed in a strong position to win the elections in next week's run-off with the centre-right Freedom Alliance. "The League got what it deserved," said Fabio Mussi, a leader of the left-wing PDS.
In the run-up to the elections the League established a separate "government" in the north and called for independence and a separate currency. Mr Bossi compared himself to Gandhi, described his detractors as riff-raff and Fascists, and dressed his supporters in militaristic green shirts.
Were Mr Bossi's an orthodox separatist movement, one could conclude that his dreams of an independent Padania, as he has renamed his core constituency, had been shattered. The elections were certainly a setback after the League's strong showing in the general election in April. But whether they will silence Italy's most voluble politician is another matter.
It has never been entirely clear if Mr Bossi is serious about secession, or if he is using it as a propaganda tool to pressure the government into delivering what his voters really want: greater local autonomy, less bureaucratic hassle from Rome and, above all, lower and less complicated taxes.
Yesterday one of Mr Bossi's most prominent lieutenants, the former speaker of the Rome parliament, Irene Pivetti, admitted that Padania was more a "poetic expression" than a geographical reality and described secession as no more than a talking-point. Yet the campaigns and threats of civil disobedience are carrying on.
Yesterday, the provincial authorities in Mantua, which are in League hands, slapped an eviction order on the office of the central government prefect for the area, a provocation intended to stir up debate on the role and questionable usefulness of the office of prefect.
The League's "government", held its first cabinet meeting in a Venetian palace loaned by an aristocratic sympathiser. And in the industrial town of Mestre, across the lagoon, a breakaway group of anti-tax protesters staged a noisy rally.
The past month has brought out the two key characteristics of the League. On the one hand, its value as a political force is severely limited.
"It dresses itself up as a national protest movement but in fact its strength on the ground is patchy at best," said another senior parliamentarian from the government benches, Diego Masi. On the other hand, as a propaganda machine and a permanent thorn in the side of the establishment, it can be remarkably effective.
The secession campaign may have outraged ministers but has also scared them into acting more quickly than they otherwise might to address the appalling tax and administration legacy of the past.
Yesterday, as the prefect of Mantua was being evicted, the Regional Affairs Minister, Franco Bassanini, admitted prefects do not do much anyway and may be abolished. He is working overtime to produce a draft law on administration of the regions within the next month and his colleagues have promised an emergency review of taxation procedures.
Top of the hit-list is the detested bolla di accompagnamento, a tax stamp that must be bought when even the smallest consignment of goods is transported. Even a takeaway pizza has to have its bolla di accompagnamento, which helps explain why almost no restaurant countenances home deliveries.