Herein, the T* fracture parameter is shown to have relevance to the mechanics of elastic-plastic fracture. Specifically, it is shown to have certain advantages over the currently established plastic fracture parameters such as J and CTOA. Finite element analyses of experimental data were carried out as a means to obtain a comparison of the effectiveness of the plastic fracture parameters. T* is clearly superior. A note on problems associated with satisfying the plastic incompressibility constraint is also included.