The laws on this vary dramatically by state and sometimes even by city. For some they can't ask or run a background check until after an offer is made. For some

The laws on this vary dramatically by state and sometimes even by city. For some they can't ask or run a background check until after an offer is made. For some jurisdictions they can't discriminate on that basis unless it's highly relevant to the job (i.e. convicted sex offender can't work with children). For some jurisdictions it's totally legal to run the background check upfront and to discriminate at will.