Marx demonstrated that capitalism as a mode of production is a structurally unstable system; this has been illustrated by the recent period, especially the current crisis. This article is a contribution to a Marxian explanation of the current crisis analyzing it as an expression of the tendency of the rate of profit to fall; it focuses on the first stage of the development of the crisis, understood as an outcome of the instability of capitalism and it identifies its specificities. Such instability is manifest through the recurrence of crises and we argue that each crisis emerges from the remedies used to counter the previous one and that it also contains the germs of the next crisis. This applies to world capitalism in general though we focus on its core economy, American capitalism.