Social movement scholars use the concept of tactical repertoires of contention to refer to the actions and strategies used by collective actors to persuade or coerce authorities to support their claims. The notion of repertoires of contention grows out of the work of Charles Tilly, who introduced the concept to explain historical variations in forms of political contention used by challenging groups. The tactical repertoires of social movements include political persuasion, such as lobbying, voting, and petitioning; confrontational tactics such as marches, strikes, and public demonstrations that disrupt day-to-day life; and cultural forms of political expression such as rituals, music, art, theater, street performance, and practices of everyday life that inspire solidarity and oppositional consciousness. Protest tactics are one of the principle strategies used by challenging groups to mobilize constituencies and to forge solidarity, oppositional consciousness, and collective identity.