Mandatory Drug testing for Welfare Recipients

I saw an interesting poll on Facebook that asked the question if you were for mandatory drug testing for welfare recipients. The real question is, why don't we have that already? In today's world, it is a rare job indeed that doesn't make you submit for testing. Some companies have random tests. Some have routine testing. If we have to submit to testing to keep our jobs, isn't it fair that we make those that live off of our tax dollars (that includes government employees and elected officials) do the same????