The class (or class alliance) in power cannot lay down the law in the ISAs as easily as it can in the )repressive) State apparatus, not only because … - Louis Althusser

I shall call Ideological State Apparatuses (ISAs) a certain number of realities which present themselves to the immediate observer in the form of distinct and specialized institutions: ...

For you and for me, the category of the subject is a primary ‘obviousness’ (obviousnesses are always primary): it is clear that you and I are subjects (free, ethical, etc.). Like all obviousnesses, including those that make a word ‘name a thing’ or ‘have a meaning’ (therefore including the obviousness of the ‘transparency’ of language), the ‘obviousness’ that you and I are subjects – and that that does not cause any problems – is an ideological effect, the elementary ideological effect. It is indeed a peculiarity of ideology that it imposes (without appearing to do so, since these are ‘obviousnesses’) obviousnesses as obviousnesses.

The reproduction of labour power thus reveals as its sine qua non not only the reproduction of its ‘skills’ but also the reproduction of its subjection to the ruling ideology. ... It is in the forms and under the forms of ideological subjection that provision is made for the reproduction of the skills of labour power.