I strongly support an increase in the federal minimum wage. Many cities, counties, and states have taken it upon themselves to implement a higher wage, but it needs to happen everywhere. I am not sure that $15 is the magic number, but it definately needs to be higher than it currently is, and by quite a bit.
A $15 per hour minimum wage is barely a living wage in many places. Raising the minimum wage is one way to help combat both homelessness and poverty. If people have the money they need to pay rent they do not have to worry about becoming homeless and they can live a better life.
Raising the minimum wage without guaranteed number of hours leaves the door wide open for the employer - through either money saving strategies or straight up cannot afford - to cut the hours of workers, meaning that they will earn about the same as with the more hours and lower wage of before. I propose a minimum salary - perhaps around $15k - that would ensure everyone be able to feed, house, and clothe their family regardless of the number of hours they work. To prevent worker abuse, I would have a yearly cap on the number of hours possible - perhaps around 1,800 hours. This would require the person who maxed out his hours to take (paid) vacation for the rest of the fiscal or calendar year.
Some small companies, or other companies just starting out may not be in a position to offer a set minimum wage. It should be up to them to offer whatever salary they want. Then it is down to the employees to decide if they would like to do that job or not. If someone is unhappy with their salary, look for another job that pays more.
Automation, robotics and AI are eliminating a number of jobs presently. A federal $15 minimum wage will only increase the push for more automation, robotics and AI. Why pay a person $15 an hour to take orders when you can provide the customer with a kiosk to input their order?