Final answer:
The statement that a common political cause may lead to violent actions by large groups for political advantage is true. The history of human conflict and the nature of acting crowds support this assertion, as does the emergent-norm theory relating to collective behavior.
Step-by-step explanation:
The statement is true: a common political cause can indeed precipitate attempts by large groups to gain political advantages or settle political disputes through unlawful means, and such situations can escalate into violence quickly. Human history is replete with conflicts stemming from political, economic, religious, or cultural disagreements. When large groups—acting crowds—mobilize around a shared goal, such as a political cause, this collective behavior can lead to heightened emotions and potentially unlawful actions.
A mass consists of a large number of people with common interests, possibly spread out, while a public is a more diffuse group sharing ideas, like a political party. When rules of standard political engagement are bypassed in favor of force, the outcomes can be shaped by violence rather than democratic processes. Political factions driven by shared passions or interests, as described by theorists, tend to lead to contention and instability, especially in 'pure democracies'.
The emergent-norm theory suggests that crowds develop their own norms and definitions of situations, which can guide their actions towards either peaceful demonstrations or violent confrontations.