Does the Left claim spray-painting someone else's building or car is "protected free speech"?

Here's a question for liberal lawyers: Is spray-painting graffiti on a building--public or private--considered protected free speech?

I think it's pretty clear that it's NOT considered free speech, but I'm looking for a persuasive counter-argument.

If you liberals can make a good case that spray-painting slogans on someone else's home or car, or on a public building, is free speech, and thus legal, I'm gonna stock up on about 20 cases of spray paint.