Outright criminalization only drives the demand for the drug to the illicit market.

CNN: Banning fake pot won't make it go away

At worst, a licit market in any of these drugs could just create new addicts for the illicit market to supply.

ECONOMIST: Legalising drugs

In such circumstances it would be hard for the authorities to prevent legally-produced opium from being diverted into the illicit market as long as the price for illicit, rather than pharmaceutical, dope remains far higher.

ECONOMIST: An alternative use for opium

Any scheme of taxation and regulation that did not leave the drugs so cheap and so available as to increase hugely the abuse problem would instead generate an illicit market not much smaller than exists under prohibition.

ECONOMIST: Legalising drugs

After decades of marijuana prohibition, elected officials and the public are finally realizing that regulating the production and sale of marijuana is the best way to reduce the harms of the illicit marijuana market and the harms of marijuana use itself.

CNN: Banning fake pot won't make it go away

The government is finally showing signs of using technology more efficiently to catch illicit behavior and market participants should beware.

FORBES: Holiday Week Ends on a High Note

Afghanistan supplies approximately 90 percent of the illicit global opiates market.

CENTERFORSECURITYPOLICY: Our long twilight struggle

Over time, the market share of illicit drugs would be steadily squeezed and trafficker income and profits would drain away.

ECONOMIST: On Barack Obama, legalising drugs, Kenya, Handel

Mr. CAMPBELL: Well, the official government explanation as to why he had to clear out all the houses was that the people were there illegally, that it was putting a strain on the infrastructure of the big cities, and that there was a lot of illegal activity, particularly black-market activity in terms of dealing with illicit currency.

NPR: Examining the Political Climate in Zimbabwe

Illicit trade is age-old, a continuous facet and side effect of market economies or of commerce in general.

NPR: Tracking the World's Black Market: 'Illicit'

From a rate of 3.4 ringgit to one dollar, the currency was devalued to 3.8, well below the then market rate, so investors had little incentive to take their money out by illicit means.

ECONOMIST: The big clean-up

Illicit trade's ancestor, smuggling, traces back to ancient times, and many a "thieves' market" survives in the world's commercial hubs.

NPR: Tracking the World's Black Market: 'Illicit'

For now, the size of the bitcoin market is so small that it could be difficult or costly to move and exchange large amounts of illicit funds.

WSJ: Web Money Gets Laundering Rule