Is the federal minimum wage constitutional?

[Fmr. Gov. NickG]

Since the 1930's, the Supreme Court has consistantly ruled that the federal government can, under the commerce clause, basically regulate anything even peripherally realted to commerce.  A couple of statutes have been struck down by our current, more conservative court, because they really had nothing to do with commerce.  But I don't know of any recent cases where a federal statute had been struck down for being insufficiently "interstate".  Even the most conservative of judges have basically adopted the FDR Court framework on this issue.

[Fmr. Gov. NickG]

The distinction about whether a particular instance of commerce is sufficiently "interstate" to warrant federal regulation is really pretty arbitrary in modern society.  We live in a national, if not global, economy.   Most people work for companies with a presence in many states, most produce things that bought in many states, or regularly do business with people in other states, or even travel across state lines to get to work. 

To exempt that small percentage of people whose business is completely contained within a single state from any federal regulation would be unjust, overly complicated, and create perverse economic incentives.  At some point, the literal constitutional wording must bow to reality.   Even most conservatives recognize this in applying federal regulation to all commerce, even though some portion may not be interstate.  Not to do so would be counter to both the stereotypically liberal goal of equality and the stereotypically conservative goal of efficiency (i.e. economic growth).

[Fmr. Gov. NickG]

The vast majority of people work only in one state.

Just because your company sells stuff in another state doesn't mean your wage is interstate commerce.

Sure it is....you are involved in the "stream of commerce," which is the relevant legal term of art.  Commerce is not simply the transfer of good across state lines, it is the entire process of economic production.