Who would be at fault in this car accident?

I was driving east down Santa Monica (2 lanes each direction) on my way to cinespia yesterday, patiently waiting in line for 40 minutes in the right-most lane as the lane of cars slowly filtered into the hollywood forever cemetery.

Shortly after I passed the last cross street, this jerk swooped in from the left lane, literally cutting into my car. After liberal use of the horn and many four letter words, I had no use but to let the budger weasel his way in line.

What would have happened, though, had I just kept going at the 5 MPH I was traveling and clipped his right front-quarter? Who would be at fault?

Surely if we were traveling at normal speeds on a 4 lane highway and someone cut into you they would be cited for an illegal lane change. And I'm sure the hundred of budging-hating lookers-on from the sidewalk (who were also waiting in line) would have supported my side of the story.