The theory is that by encouraging staggered closing times, the thousands of customers who roll out onto the street at am would be dispersed over the night. This would take pressure off of SPD, allowing them to do better, more focused enforcement. It would also help curb drunk driving (at 2 am there is little taxi cab availability due to the spiked demand for cabs with everyone settling up at the same time.) There would also be less concentration of noise on the streets at 2am solving one of the most frequent complaints from downtown residents. And of course with an increase in operating hours comes an increase in revenue (and jobs) for bars, and in turn, more revenue to the State and City.
Current State Liquor Laws mandating 2am closing for liquor licensees would need to be changed, but this would not take legislative action, and the program could be limited to Seattle for a limited test period.
In the US, many cities and states have already implemented staggered or extended liquor service hours. Birmingham, Alabama allows 24-hour liquor service along with Atlantic City, Memphis, parts of Miami, and all of Nevada and Louisiana, and some counties in Illinois.
And other states and cities now have expanded liquor service hours anywhere from 3:00 am (Tampa, Illinois, Indiana, New Jersey, Tennessee), 4:00 am (Hawaii, Broward County, Louisville KY, New York State) to 5:00 am (Alaska, the Jersey Shore).
In 2005, England and Wales started licensing 24 hour liquor establishments, and Scotland is now joining them. England has seen decreased in alcohol related crime and violence. New South Wales in Australia, Belgium, and Israel also have no mandated closing times.