Experts who study protest movements say the scenes unfolding in California broadly follow a script that has played out many times in other countries — sometimes with deadly consequences.

© Philip Cheung for The New York Times

Miguel Uribe Turbay, a conservative presidential hopeful, remained in “extremely serious” condition on Sunday, a day after being shot.

© via Reuters

The brazen attack, captured on video, recalled the political violence of past decades. The senator arrived at a hospital in critical condition.

© Sebastian Barros/NurPhoto, via Getty Images