If you paint it, maintain it!

This colorful mural was created beneath an underpass near an entrance to the Bronx Zoo. As you can see, it was defaced by some wiseguy who wanted to make a unique artistic "statement."

Those who advocate murals in public spaces need to be responsible for them. If somebody defaces the mural, then the people who sponsored it ought to have it immediately re-painted. This is the best way to stop graffiti; get rid of it as soon as it appears. Ideally, murals should be covered with a special graffiti-proof sealant, so that any future vandalism can simply be wiped off.