Decriminalization and Legalization – what do they mean?

Much has been made around the drug policy blogosphere in the past day regarding a gotcha moment with Barack Obama regarding decriminalizing marijuana.
The Washington Times, in a backhanded hit piece on Obama found a video statement from 2004 where he said he supported decriminalization (but not legalization), and then the article pointed out the fact that Obama raised his hand in last fall’s debate saying he didn’t support decriminalization.

Asked about the two different answers, Mr. Obama’s presidential campaign said he in fact has “always” supported decriminalizing marijuana as he answered in 2004, meaning the candidate mistakenly raised his hand during the presidential debate last fall.

This led a number of people naturally to get somewhat excited that Obama was supporting decriminalization, both from our side, and the opposition (the Times was pretty quick to get that in an editorial and tar him as left-liberal for it).
And then, a short time later…

When confronted with the statements on the video, Obama’s campaign offered two explanations to The Times in less than 24 hours. At first, Obama spokesman Tommy Vietor said the candidate had “always” supported decriminalizing marijuana, suggesting that his 2004 statement was correct. Then after The Times posted copies of the video on its Web site, www.washingtontimes.com, yesterday, his campaign reversed course and declared he does not support eliminating criminal penalties for marijuana possession and use.
“If you’re convicted of a crime, you should be punished, but that we are sending far too many first-time, nonviolent drug users to prison for very long periods of time, and that we should rethink those laws,” Mr. Vietor said.
The spokesman blamed confusion over the meaning of decriminalization for the conflicting answers.

So it’s a lot of hoopla, but nobody seemed to have a clue what language they were speaking.
It’s true — decriminalization is a pretty messy word. I avoid it like the plague.

Decriminalize: To reduce or abolish the criminal penalties for

Not much clarity there. Reducing the penalty somewhere for marijuana possession from 2 years to 18 months would be decriminalization.
I’ve heard some people say that decriminalization means you wouldn’t be arrested for using marijuana (but you would for selling it). Some say it means a fine instead of jail time. Still others use it as a way of meaning “legal and regulated” and then consider legalization to mean completely unregulated.
I think drugs should be legal (through legalization or re-legalization, if you prefer). So it behooves me to identify exactly what that means.
So here’s the definition I propose:

When a drug has legal status, it means that a responsible adult may, in some way, openly obtain and use the drug for recreational purposes with no legal penalties. There may, however, be regulations regarding the purity/quantity of the drug, and the time/place/manner of its sale or use.

I think that this is a good template for defining the legalization of any drug. It allows for a wide variety of options with different drugs, and clarifies that legalization doesn’t have to mean a free-for-all (although unregulated would be one of many options).
Now of course, such a definition would allow some legislators to over-regulate (“Marijuana smoking can only occur in a single-family home with the blinds closed and only on the 29th day of any month that begins with the letter ‘F'”), but we’ll always have to contend with idiots.
What do you think? Any changes to the definition?