For decades, the issue of cannabis reform was firmly viewed as a leftist pipe dream. To most conservatives, particularly US Republicans, legalising weed was as realistic as nuclear disarmament, or abolishing national borders. Think of the phrase “war on drugs” and the first people that probably come to mind are Republican presidents Nixon, Reagan and George HW and George W Bush. Although the clampdown reached its harshest levels during the presidency of Mr “I didn’t inhale” Bill Clinton, it always seemed as if the GOP owned the position of being…