Diracs argument for electric charge quantization (ECQ) is not to be ta — Robert Marshak

"Diracs argument for electric charge quantization (ECQ) is not to be taken lightly because it is the first "topological conservation law" uncovered in Abelian gauge theory. Since Diracs two papers on the magnetic monopole were published, other potential physical examples of "topological conservation laws" have been identified in non-Abelian gauge theories (e.g. instantons, t Hooft-Polyakov magnetic monopoles, etc.) which have revealed the rich topological structure of QCD ... Moreover, with regard to Diracs ECQ argument, it is likely that — within the framework of the standard model — ECQ is well explained by the chiral gauge anomaly-free constraints, which, to some extent, contain topological information ..."