system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did marijuana suddenly become legal in 3 states? Why is there such a sudden change in sentiment?
gpt
I wouldn't say that it's been a "sudden" change in sentiment.  The legalization movement had been gaining traction for quite a while.

Two big tipping points, however, are probably due to 1) the growing realization that the *War on Drugs* has been one colossal—and expensive—failure, and 2) the nuanced view the Medical establishment has taken on the use of marijuana for medicinal purposes.

EDIT: Several big tipping points!