States together spent somewhere around $3.6 billion enforcing marijuana possession laws in 2010, according to a new study by the American Civil Liberties Union, entitled "The War On Marijuana In Black and White." That's the authors' "best estimate," though approximations using different methodologies put the cost as high as $6 billion and as low as $1.2 billion.
The paper grabbed headlines Tuesday with its finding that blacks are nearly four times as likely as whites to be arrested for possessing marijuana, despite both races using the drug at about the same rate.
(Read more: Gallery of Medical Marijuana)
Here are some most startling numbers from the ACLU's report with regards to the cost of enforcing marijuana laws:
$20 billion: The amount states will spend enforcing marijuana laws over the next six years.
$900: The minimum per-capita cost spent by California, Nevada and Washington on criminal justice for marijuana offenders.
$750: The low-level estimate that states pay for each marijuana arrest.
$95: The national average per-diem cost of housing an inmate arrested due to a marijuana-related offense.
$2: The average amount communities spend each day on marijuana supervision.
Previous attempts have been made to assess how much energy law enforcement expels enforcing marijuana possession laws. One such report from earlier this year found that the New York Police Department spent 1 million hours enforcing low-level marijuana offenses between 2002 and 2012. Another study from 2012 found
that a marijuana-related arrest is made every 42 seconds in the U.S.