The crucible is Portadown, 30 miles ( 50 kms ) southwest of Belfast, where Orangemen march each July from their rural church back downtown _ through the town's main Catholic area. Protesters from several Catholic communities crowded into Portadown's Catholic Garvaghy Road to hear speakers demand negotiations with Orange Order leaders, and pledge to (participate) in each others' road-blocking protests this summer.  
 Verb: participate
Yes