Is the Molson's (Canadian) beer sold in the U.S. watered down?

Today's Straight Dope column is a reprint from 1986, in which Cecil Adams tackles this question:

Does my jaded palate deceive me, or is the beer exported to the U.S. by Canada and other countries in fact different from what they sell at home under the same label? I am sure you can appreciate the international significance of this issue.

Read Cecil's answer at The Straight Dope.