Legal Question in Intellectual Property in California

Re: copyright law

Risky is probably the best term. Copyright law allows "fair use," which includes the right to quote to a limited extent, and possibly also to copy artwork for very limited purposes such as reporting news or critical review. It is pretty easy to step over the line. I'd advise getting a publisher's self-help law book and doing some reading about the limits of the fair-use doctrine. If ever in doubt, ask for written permission.

Also, it's probably reasonable to point out that penalties for innocently overstepping the bounds of "fair use" are based on proof of damages, and if you are neither making a big profit nor depriving the copyright owner of significant profits, there is little incentive to sue you.

Re: copyright law

Not without permission of the copyright owner... likely either the cartoonist or the publisher.