FDR signed the Fair Labor Standards Act into law on June 25, 1938, which included a national minimum wage (originally set at 25¢ per hour), defined the standard work-week as five 8-hour days, and capped overtime at 4 hours per week.  The intention behind the minimum wage was that an employee who's either just getting into the job market or is learning a new trade should be protected against "employer exploitation" while they're learning the ropes and mastering the requisite skill set.  The concept makes sense, and if it'd stayed that way, I'd wager that the minimum wage wouldn't be half the political football that it is now.

Unfortunately, the labor unions got hold of the post-war minimum wage by indexing their labor contract pay scales to a multiple of the minimum wage, giving the union lobby (and their Democrat Party proxies) the incentive to increase the minimum wage as often and as high as popular sentiment would allow.  If the original minimum wage were adjusted for inflation, then today the rate would be $4.13 hourly, ± 4¢ depending on who's doing the math, yet the current national minimum is $3.12 an hour higher than that.  Thinking as a businessman (or perhaps as a classical economist), how many more jobs would become available if the minimum wage were restored to its original purpose, and the rate were deflated to its inflation-adjusted original level?