And you've been getting answers for weeks. The fact that you don't like the answers, especially when they point out that your question is flawed, is not our problem.
Easy and obvious answer, Howlin: Because they want to get on with their lives. Because they don't want to go to bed every night wondering if tomorrow will be the day they're charged. It doesn't matter if you're innocent; prosecutors can certainly still make your life a living hell.
It's super easy to sit back and theorize about what you would or would not do. It's a different matter when it's your reality. Thankfully, I've never been through anything like this, but I had a friend who did. He refused to deal, went back and forth with them for years without ever being charged. Spent every nickel he had on legal bills, and then the prosecutors said, "Ah, guess we'll move on now. Have a good life." That's reality. And that's why innocent people sometimes make deals.
MM
An attorney's first order of business is to minimize the consequences of a legal action against his client. Ultimate guilt or innocence is usually a secondary concern.
Regarding Rush, one has to read between the lines. Given what I understand of his situation, he probably did violate state and perhaps federal laws while arranging his self-medication. Also, from what I understand, most prosecutors would probably drop charges against first-time offenders who had sought treatment (regardless of other issues, such as Rush's prominance).
Given the prosecutor's zeal in pursuing Rush (and leaking to the media, if so), it seems to me that there is certainly a defamation project under way against Rush. This is most likely the work of the DNC and their cohorts in Florida. Like Rush or not, this is a battle that conservatives should join.
To make the situation go away.
The Fed and the states certainly disagree, but quite frankly it is none of their damn business what people might choose to put into their own bodies or how much. It is not the Fed's business what is sold inside of states, and arguably it is none of the state's business what trade occurs between adults not dealing in stolen property. If you want smaller government and a government focused on it's legitimate role, then I suggest we get government out of the drug war. Then maybe it could focus on solving violent crimes and keeping violent criminals locked up. If the Fed had not been so busy being drug warriors, they might actually have been focused on terrorism enough to have had a better shot at preventing 911.
The War on Drugs is a proven failure. There is absolutely no evidence that it affects drug use in America at all. The only demonstrable effect of the War on Drugs is to raise the price of the drugs. Addicts become critically ill without their drugs. If they cannot afford to buy them on their conventional wage scale, they are forced to turn to crime to fund the costs of their addiction. The War on Drugs turns addicts into criminals, turns law enforcers ranging from the cop on the beat to jailers to judges into criminals. It has the potential to lead to the corruption of public officials at the highest level of public office. And there is not a shred of credible evidence of any positive benefit to a single member of society.