If the federal minimum wage is $5.15, how is it possible that some states have a lower minimum wage or no minimum wage at all?
There aren't a lot of jobs that aren't covered by federal minimum wage laws,
Who is covered Anyone working for a company making more than $500,000 with 2 or more employees is covered, plus people in other jobs. Also people who engage in interstate commerce are included. An example is a secretary who types a letter that is sent out of state.
Since most jobs are covered, many others are effectively covered for competitive reasons. Someone you can trust to work without immediate supervision is not going to work for $4.00/hour.
Some of the blue states have $5.15 laws that extend the coverage of the federal law. For example, Georgia covers any company with 6 or more employees.
The Kansas law is $2.65, which means for all practical purposes they are a yellow state, but have an old law that has never been updated.
The Ohio law has some step ups for very small companies. If they had to pay more, they probably wouldn't hire anyone.