Correlation or Cause?

What issue do these five groups have in common?

1) Police Unions

2) Private Prisons Corporations

3) Alcohol and Beer Companies

4) Pharmaceutical Corporations

5) Prison Guard Unions

Hint: They are all opposed to a current reform issue favored by a majority of U.S. citizens.

Yes, indeed it's the legalization of marijuana. Too much federal drug enforcement money flows to police departments. Too many prisoners locked up for minor drug offenses. In fact, we wouldn't need a single 'private prison' if pot were legal. Alcohol and Beer -- Duh! 

But the truly sickest opposition comes from the pharmaceutical industry. If cheap pot replaced dozens of their high-priced pills what would happen to corporate profits. Never mind that cannabis is safer and more effective than the chemicals being pushed by the corporate drug giants.