If it seems like the issue of graffiti never goes away in Portland, well, that's because it doesn't.

These vandals don't seem to ever run out of spray paint. Consequently, the city and its business community has to have an unending supply of determination. Really, that's the only way to combat graffiti. The scrawls have to be removed as quickly as possible, even at considerable expense.

As a story in Tuesday's newspaper pointed out, that expense can be high. Sand blasting graffiti off of bricks high up on a building can easily cost $1,000 - and that's just dealing with one offense.

The price of doing nothing, however, would be far greater. Experience teaches that when graffiti is left to linger, it draws more spray-painters. Worse, graffiti can undermine policing efforts, acting as an invitation for other crimes.

So, as both a matter of aesthetics and as a crime-prevention measure, it's important Portland stay on top of the graffiti problem.

There are both public and private efforts to combat illegal artwork in Portland, and that's appropriate. The city has an interest in keeping down graffiti because doing so makes the job of police easier. Private property owners, meanwhile, risk their investments if they allow graffiti to take over. This, as Tuesday's story pointed out, is of special concern during the holiday season when downtown merchants want to keep the city attractive and competitive with other shopping venues.

Besides getting graffiti down as quickly as possible, the city and its businesses are also working to prevent graffiti from happening in the first place. These efforts include better lighting and other security measures as well as a commitment to report the vandalism to police promptly.

These steps all make sense, but unfortunately it's a never-ending struggle.