Much of the meth in the US now comes from Mexico. It is rumored to be more potent than the home made stuff. A few years ago OK made it very difficult to buy Sudafed over the counter, one of the first states to do so. Meth lab busts in OK have gone down dramatically since the enactment of that law.
For a long time the US congress refused to restrict the availability of Sudafed. Congressmen have long been in the pockets of the drug companies and the drug companies wanted to continue to sell Sudafed by the boxcar load.
40 states passed laws restricting the sale of Sudafed before congress got its act together and did the same.