Importing prescription drugs from Canada is tougher than it sounds

American politicians love to say they'll let Americans import cheaper prescription drugs from Canada. But there's a problem: Canada.

What they're saying: Canadian officials' internal briefings say that the country "does not support actions that could adversely affect the supply of prescription drugs in Canada and potentially raise costs of prescription drugs for Canadians," according to documents obtained by Reuters.

Importation into the U.S. would fit that bill. If we really did begin importing large quantities of drugs from Canada, its domestic supplies could shrink.

• Pharmaceutical companies would have every incentive to either limit Canada's supplies, to ensure that not many pills make it back across the border, or to try to raise their prices in Canada.

There are other problems, too, despite importation's political popularity here.

• The FDA has consistently resisted large-scale importation efforts, saying it can't adequately guarantee those products are safe.
• Drugmakers' purchasing contracts in Canada also often prohibit the practice, per Reuters. (Canada's federal health care does not cover prescription drugs — they're covered through a mix of provincial programs and private insurance.)

My thought bubble: If the U.S. wants to set some standards about how much it will pay for drugs, we always have the option of setting our own rules rather than importing Canada's.

Go deeper: The U.S. won't import prescription drugs from Canada any time soon