You know, Sowell used to be a hard-core marxist when he was younger.
Then he grew up.
Yes, he was, and he addresses it right here in the first few seconds:
[ame=http://www.youtube.com/watch?v=5KHdhrNhh88]The Difference Between Liberal and Conservative - YouTube[/ame]
That's actually how I came to know of it as well.
You can tell he was pretty adamant about it as well, as he remained a marxist even after spending a year studying under Milton Friedman.
But I guess you have to experiment things for yourself in order to correct such a big ideological flaw; such as the belief in socialism.
If you're not a liberal at twenty you have no heart, if you're not a conservative at forty you have no brain. ....Winston Churchill