Which is the greater journalistic sin?

Is it worse to make up a quote to complement your argument, a la Jonah Lehrer, or to plagiarize another author's work, a la Fareed Zakaria?  Or maybe they're both offences equally egregious sins?

The more I think about the issue the more I'm inclined to think that fabrication of content is a greater sin, and is generally more likely to cause more harm, than plagiarism, though that doesn't mean that plagiarism isn't problematic in its own right.