Why did so many voters draw to harding’s message of normalcy and a return to values of the past?

Harding used the message about the return to normalcy, about the "return to the way of life before WWI", as the main slogan during his presidential campaign for the election in 1920. He promised the acquisition of that pre-war mentality by simply dealing with the war issues through healing, restoring and adjusting, in a non-dramatic manner, and this would enable to go back to the previous triumphant mentality.

the constitution gives congress the power to regulate commerce "among" the several states.