When you look at the ways Italian Fascism established its hold on the institutions of the Italian State – and especially if you investigate how strong this hold was, beyond the large degree of surface consensus – it is natural to compare it “unfavorably” to the German Nazi Regime.
It is generally accepted that the National Socialists were able to secure control of the highest organisms of the State, or to behead or completely isolate competing powers in a quicker and more decisive manner. While this may be a slightly oversimplified version of the Nazi rise to power – and I hope someone will point out possible inaccuracies (I am not, after all an expert on National Socialism) – it's the one I am going with. With this broad picture in mind, it is fair to say that Italian Fascism was slower and, to a degree, less effective; provided that one considers the two regimes as political formations with parallel goals, running more or less on the same tracks.
This idea derives in part from the realization – and a fair one at that (see for instance the usual references: R. Paxton's Anatomy of Fascism and S.G. Payne's Fascism) - that both Italian Fascism and National Socialism underwent with time an organic process of radicalization, which is, again, more pronounced in the German example. To the point where the Italian case appears in comparison almost incomplete. That is – if we looked at Fascism and National Socialism in the form of an epidemics – National Socialism would be the most severe form of a similar disease, the life threatening one, while Fascism would appear a more “tolerable” one. While this approach provides for a somewhat evocative picture, it does not necessarily result in an accurate representation of the two regimes.
Organic radicalization is after all a way of pointing out that the seeds, the causes, the building lines of this radicalization were present within the Regime, that the vague ideological elements, the cultural suggestions and practical end goals of the National Socialist and Fascist leaderships were consistent in a large measure with such a process of radicalization – it does not mean by necessity that such a radicalization was in itself the end goal, that the most extreme form of the regimes was the necessary outcome of a well coordinated effort. The effort was there, but the end game was less coherent and the radicalization somewhat more spontaneous.
Under this slightly different point of view, it's worth at least questioning if the National Socialist “effectiveness” in establishing their Regime should be taken, even in context, as a “positive” feature.
What is beyond question though, is the fact that the Italian Fascist Regime had – after almost twenty one years of Mussolini's “premiership” - a surprisingly weak foundation; at least if we judge from the fairly easy and straightforward process that led to Mussolini's dismissal by the King in July 1943. And the King himself – an elderly man who had never been considered a master schemer, and who had risen to the center of the internal opposition to Mussolini under the pressure of the disastrous war events – found minimal opposition to his decision to get rid of the much beloved Duce of the Italian Empire.
Even if the subsequent twenty months would prove fraught with conflict and misery for the Italian population, the immediate reaction was one of substantial composure, moderate relief (to the perspective that the war was going to end soon) and occasional outbursts against the Regime. The State administrations were able – at least on the surface and for the brief period of six weeks – to maintain control of the ongoing matters, with the functionaries, the police and the army inheriting some measure of control over the nation. And these apparently weakened ruins of the old pre-Fascist State held together for a while, despite being abruptly deprived of their Fascist sustenance.
A fact which has led certain observers (see for instance F. Chabod's Storia dell'Italia Contemporanea) to underestimate perhaps the degree of consensus enjoyed by the Regime in the build up to war. There are nonetheless various indications that the consensus was substantial enough – that is, the Italian population approved of the Regime well enough, but not enough to die in scores for it, if an alternative was provided. Which is probably a fair assumption to make about consensus towards political formations in general.
On the other hand, when certain groups begun to look for an alternative to Hitler's leadership in Germany, the perspective of an alternative center of power – and for the population the idea that a way out alternative to the Regime was possible (a point this one where the Nazi propaganda machine proved indeed more effective than the Fascist one) – was an extremely remote one. There was very little power left.
And this would be our first and more “objective” explanation: Hitler's rise took place within (and in part thanks to) an abrupt vacuum of power, that was further expanded by the Nazi leadership's political choices. The loss of the President, Hindenburg followed that of the Emperor of only fifteen years before – the Reichstag fire did not only offer the Nazi leadership a chance to enact extremely punitive measures against the oppositions, but also served as a symbol of the final crisis of the Weimar Republic. In addition to this, Hitler took a much more energetic approach to threats against his leadership (at least to those he choose to perceive) – the result being that (returning to metaphors) the Nazi approach was to vastly demolish the previous institutions of the State, and to operate at times in absence of a proper substitute or in exception to whatever leftovers were in place (please correct me if my understanding of the heuristic Nazi approach to “legal” issues is incorrect).
For Italian Fascism, no such major vacuum of power was created. Mussolini took power as a leader of a large coalition Government (which comprised all parties with the exception of socialists, communists and a few minor forces) and continued to operate in coexistence – formal and often practical – with most of the institutions of the old State, and for a while even with the old parties. Some of these were dismissed (the Parliament lost its function almost completely after the murder of Giacomo Matteotti and the Aventine Crisis in 1925) with the entire representative system (a major loss for the budding forms of the Italian liberal democratic system – but less dramatic for the other centers of power, which often sought and found alternative ways to exert their influence within the growing Fascist system), others were reworked into the organization of the Regime (it might be of some interest to follow the Regime's approach to one specific industrial sector – that of radio communications – to see an example of what I mean), and others continued to operate as parallel and competing centers of power: the King and the Church.
Much could be said of the relations between the Fascist Regime and the Church; and the King (and the Army) as well. What matters for the question at hand is the fact that – through ups and downs in their mutual relations – the Fascist Regime had to grow around two major pre-existing centers of powers, like a tree adapting to a metal structure that was already there and could not be removed.
While the Regime was able to increase its power, at times at the expense of these competing forces, there was never a time when Mussolini could realistically treat the Church and the King as he did with his other internal opposition (the residual forces of the liberal system, certain industrial groups, a few more unruly gerarchi) - that is, he could never “manage” them: he had to deal with them (more or less on an equal ground). Mussolini's claims that he could get rid of the King if he wanted were more of a way to keep his hold on a certain fringe of more radical tendencies, than anything resembling a concrete political program – and taken by most as non sequitur.
This created a pattern of reciprocal influence that extended to the whole of Italian society, with its smaller and larger subsidiary groups. In a way, one should also remember that the fascist look on the institutions of the old Liberal State is not the only one that matters: the Church and the King, as well as any other group had their outlook on Fascism as well – some of the forces which had looked favorably to the affirmation of Fascism through its early pre-regime years, continued to do so, and continued to pursue a “manageable fascistization” of the State: Fascism was not that authoritarian-conservative state that some had conceived as a reaction to Bolshevism in the early 1920s, nor exactly what the Nationalists had envisioned in the 1910s – but it was close enough; and under many regards it continued to serve its function and to provide some compensation for those groups which chose to remain within the narrowing boundaries of the Italian system.