Following an attack on a German member of the European Parliament in Dresden, his party has warned not to treat the incident as an isolated case, as hundreds took to the streets in the eastern German city in solidarity with the severely injured lawmaker. “It is very clear that this willingness to use violence did not occur in a vacuum,” Saskia Esken, leader of Germany’s ruling Social Democratic Party (SPD), said ahead of a rally in Dresden on Sunday afternoon. A 17-year-old turned himself in to police earlier on Sunday following the attack on Matthias Ecke, who represents the SPD in the Europe…