Riot police seize a protester at the G-8 and G-20 summits in Toronto in 2010. Protests at this month's NATO Summit in Chicago will miss an opportunity to double up on the G-8 because President Obama moved it to Camp David. (Associated Press)

Riot police seize a protester at the G-8 and G-20 summits in Toronto in 2010. Protests at this month's NATO Summit in Chicago will miss an opportunity to double up on the G-8 because President Obama moved it to Camp David. (Associated Press)