The plight of embassy workers is very real and something must be done to make diplomatic immunity not be a license to break the law.  The workers and their passports must be subject to American legal protection, whether by treaty or American law.

Unions and minimum wages are a great interim step, but simply playing around with raising them is not enough. Ownership and control of the enterprise by workers (through their unions) is essential to move beyond where we are now.  It will be harder to undo than a minimum wage increase (which inflation erodes with time).