For many decades Canada has been the largest importer of U.S. goods. Currently Mexico is 2nd and China comes in 3rd. But in the next two decades, China is expected to top Mexico as the second largest trading partner. That is because China’s share of U.S. exports could more than double over the next 30 years. I doubt China will ever overtake Canada, as the frozen north has always been the largest importer of U.S. products by a wide margin. And going the other way, the U.S. has always been the number one destination for Canadian goods.