The nature of the chemical bond in 1,3-butadiene is analyzed by applying the recently developed generalized product function energy partitioning (GPF-EP) scheme, which allows the calculation of the quantum mechanical interference contribution to the energy in a meaningful and intuitive fashion. The method is applied to investigate the breakage of the middle C-C bond, and the rotation along the torsional angle defined by the carbon atoms A comparison between bonding in ethylene and butadiene is also performed. It is shown that bond delocalization plays no role in the properties of a conjugated molecule and that existing alternative explanations should be revisited.