Illinois townhome association not paying for structural damage

I live in a four-unit town house. The two end units are ranch units and the two middle units are raised ranch units over the end units. The two middle units are experiencing severe cracks in the walls. The townhome association says that if the cracks are the result of the building moving, they are not responsible. Is this accurate? I can understand the association not being responsible for repair of the cracks but who is responsible to repair the structural problem?