That is the commonly stated reason for the enactment of the minimum wage, the so-called 'baptist's reason' (in the bootleggers and baptists paradigm [1]). Historically the minimum wage has been used to discriminate against minorities and other targeted groups by making their wages higher than their value to an employer[2], this would be the so-called 'bootlegger's reason'.

[1] http://en.wikipedia.org/wiki/Bootleggers_and_Baptists [2] http://www.amazon.com/State-Against-Blacks-Walter-Williams/d...

edit: if you follow the money on the bootleggers side, you will see that unions and companies with high capitalization support increasing minimum wages.