There was no reason to make it illegal in the first place. The US army did a large study in Panama years before and found no adverse effects on the troops. The Mexicans that were associated with it at the time caused racism to be the main influence in characterizing it as potentially dangerous and setting up the "stamp" issue. I do not smoke it personally. (flame suit on)
Be careful what you wish for...legalization will be followed by MASSIVE taxation, and the price will skyrocket, causing the same black market that exists today.
The difference will be that the price will undoubtedly rise (due to taxes), and the supply will continue to be mainly from illegal sources.