Why did the student protesters sit outside the Democratic National Convention?

Its 1968 as delegates flowed into the International Amphitheater to nominate a Democratic Party presidential candidate. Tens of thousands of protesters swarmed the streets to rally against the Vietnam War and the political status quo. they were there to protest the Vietnam War that took place prior to and during the 1968 Democratic National Convention. In 1967, counterculture and anti-Vietnam War protest groups had been promising to come to Chicago and disrupt the convention, and the city promised to maintain law and order, and in 1968 they did.