The nationalization of the banks of the economy of a country is basically a nationalist policy. Nationalism and the nationalization of the banks are one and the same. This is why the Eire Nua programme of Provisional Sinn Fein, if my memory serves me right, could happily call for the nationalization of the banks. It is not a revolutionary communist position.
Communists are internationalists and thereby support the socialization of the forces of production on a world basis. Consequently they don't support nationalist solutions to what are global problems. Nationalizing the banks is a policy that can be realised within the context of capitalism. It is not a communist policy. Bank nationalisation does not necessarily solve the problems of the working class. Banks may be nationalised and yet fail to meet the most basic and obvious needs of the working class. Nationalised banks can be just as ruthless and merciless in their relations with their working class clients as any private bank. There have been state companies that produce commodities yet fail miserably to show compassion towards the working class. This because, like all capitalist enterprises they are the subjects of the law of value.
Even with the nationalisation of the banking system the banks must still observe the laws of capitalism. Otherwise they go out of business. They cannot, simply because they are nationalised, transcend the law of value. Nationalised banking is sometimes the preferred policy of the bourgeoisie or at least sections of it. Even if nationalised banks are still involved with the money-form --with capital in the form of money. Likewise they they are subsumed under credit relations.The latter are inseparably based on the money relation.The money relation is based on the circulation of commodities and in particular the circulation of capital in the form of commodities. The circulation of commodity capital is in turn rooted in the valorisation process. This being so the banking system implies the capitalist reproduction process.
State banks under workers control is a paradox. Because of their very nature state banks can never be authentically under workers' control. It is like saying that capitalism can be under workers' control. If banks can be subjected to the democratic control of the working class then so too can capitalism. Then communism cannot be a historical necessity. Capital by its very nature precludes its subjection to the control of workers. Trotskyism, inspired by Trotsky's 1938 transitional programme, has made nationalisation under workers' control a important plank in its programme. The 1938 transitional programme attempts to go beyond the minimum/maximum programmatic framework. But the former is a flawed programme that merely reinforces confusion within the working class movement. There can be only be communist programmes. Communist programmes always make it clear that communism is the aim --not socialism. Communism necessarily entails a state-free classless society.
Communists can only logically promote communist social relations. Communists social relations by definition transcend the relations of capital: bank relations, money relations and of course value relations in general. Communist relations preclude the existence of banks and the exchange value they express. Communist relations constitute the antithesis to bank relations whether private or public. The former are directly visible relations while the later are relations of reification. Consequently commodities cannot exist under communism. Products cannot assume the form of commodities under communist relations. They are just products. Consequently money and banks are superfluous. Goods are produced and distributed according to the popular democratic decisions of the community.
Even some figures within Stalinism and Trotskyism are aware that any nationalisation of banks carried by the Irish government under current conditions is not nationalisation in the sense that Lenin and Trotsky would have meant. Some call it a phony nationalisation.Dan La Botz writing for Monthly Review says that
"Bank nationalizations in reality, however, have usually just been a stage in the boom-bust cycles of modern economies, a period when the state lends its strength to finance to see it through hard times, and once finance has recuperated, the state returns it to its private owners so they can continue to reap the benefits of wealth plus interest."
I shall end this piece with a quotation from Engels:
"But of late, since Bismarck went in for state ownership of industrial establishments, a kind of spurious socialism has arisen, degenerating now, and again, into something of flunkeyism, that without more ado declares all state ownership, even of the Bismarckian sort, to be socialistic. Certainly, if the taking over by the state of the tobacco industry is socialistic, then Napoleon and Metternich must be numbered among the founders of socialism."