Some use the word fascism as descriptive of the Islamic Republic or Muslim movements. The use of this term could impart a particular political meaning that is easily interpreted as a declaration of war on these movements and institutions or adoption of a series of policies that would directly lead to a war, particularly with the Islamic Republic of Iran.
Some leftists and communists in line with Lenin's thesis on "National and Colonial Questions" see these movements as "national liberation movements" and see long term alliance with them as a means of broadening the fight against "imperialism". "National and Colonial" thesis of Lenin is the direct byproduct of his thesis on "Imperialism". Lenin's theories yet have an enduring influence in the underdeveloped societies. Nevertheless this view has weakened, particularly with the 1979 uprising in Iran and some leftists who cannot swallow the backwardness of these movements tend to oppose it. But in general, leftists tend to view fascism as a byproduct of "decaying" capitalism and they would not miss an occasion to raise their warning flag of the impending takeover of the modern world by fascists.
One of the most well known theoreticians of the left on fascism has been Leon Trotsky. His views are compiled in "Fascism: What it is and How to Fight it". His theory is very simple. The rise of fascism is the best indicator of the decay in the capitalist societies. Furthermore he said that the victory of fascism in Germany and Italy, in the first half of the last century, is the penalty that the working class of these countries had to pay for failing to take power and establish their "dictatorship" over the capitalists. Trotsky's solution was that the workers need to organize against fascists and go as far as creating squads that would attack fascist meetings and their establishments. Also during the war between the democratic capitalist societies and the fascists as in WWII, a true communist had to refuse to aid the allies and instead should have worked for the defeat of his country. His logic was that workers do not have any interest in an "imperialist" world war. That was WWII and an American communist was supposed to be for the defeat of the American armed forces. It sounds ridiculous but that is the essence of Trotsky's theory and some yet peddle it.
If the communists musings with their theory of fascism had any truth to it then after so many decades past their prognosis, with the demise of many "socialist" states, the capitalist crisis must be even deeper and the democratic capitalist societies should be awash with fascists. Communists and the leftists fallacies on fascism run deeper but I think enough said for now.
In reality the Islamic movements of today and the European Fascism of the last century do share a common trait. Both seek national solutions for the crisis they are facing. Both convince the population that there is something in their past that could be used as an emblem of superiority and salvation. In the case of Germany, Italy and Japan this "national" fervor of fascism spilled over the national boundaries, starting WWII and could only end with their military defeat. The alternative would have been incomprehensible in terms of the setback to human culture.
In case of Iran, after the 1979 uprising, Islamists made a few attempts to spill over their boundaries but it could not be sustained. In this context the machinations of the Islamic Republic to gain more influence in the region is important to note. On the one hand, the attempts by the Islamic Republic to acquire nuclear power and potentially nuclear arms, is a danger sign which needs to be rebuked without hesitation. On the other the backlash against the Islamists in Egypt and recently in Turkey seem to indicate a more profound crisis in the "national" salvation calls of the Islamists. It is unlikely that Islamists could cause another world war, but all indications are that pushing them back will not happen without confrontations.
In any case calling the Islamic movements as fascists signals a heightened level of danger that is unwarranted. We need to call them by their real names, Islamic movement, Islamic Republic, Muslim Brotherhood or whatever name they adopt and confront them accordingly.