If you click directly on the link in David's original post, you get a New York Times error message. Clearly, part of the link works since you at least get to the NYT server.

If you cut out the link text and paste it into the browser, you get a generic 404 error.

If you cut out the link text, paste it into the browser and delete the space before 'html' in the link text, you get to the desired Krugman article.

The only question is how the space got into the link text; it's not a Mac thing.