The direct consequence is that these people, who want jobs, contribute less to the overall economy than they use in the form of public assistance.
Liberals seem to be unable to make this connection. They seem to think that we can just print more "dollars" out of thin air with no consequence. The real consequence is that our currency has lost 95%+ of its purchasing power since the establishment of the Federal Reserve System through dilution of the currency.
The world is starting to wake up to this deceit and this government sponsored ponzi scheme will only continue as long as our currency is accepted as the world reserve currency.