Thousands gathered in Union Park before beginning their march to the United Center, where the convention is taking place.
Protesters carried signs and banners reading, "End State Violence From Chicago to Gaza" and "Dems' Silence = Israel's Violence."
Organizers—who hoped to see 15,000 people in the streets—have expressed alarm in recent months over the Chicago Police Department's aggressive response to pro-Palestinian protests, with a legal coalition last week expressing concern about Police Superintendent Larry Snelling's intimidating comments about arresting protesters and other issues, and city officials have clashed with organizers about the route the march will take.
But threats of arrest did not deter groups including Jewish Voice for Peace from joining the march, with the local chapter saying its members would "make clear our commitment to freedom and safety for all people, from Chicago to Gaza" and as they demanded an "arms embargo now."
Organizers of the Uncommitted movement, which emerged during the Democratic primary season to pressure President Joe Biden to end his support for Israel's assault on Gaza, continue to press the Harris-Walz campaign to break with the administration's position.
While Harris initially indicated to the group a willingness to discuss support for an arms embargo earlier this month, a top adviser for the Democratic nominee said soon after that the vice president does not support ending weapons transfers to Israel.
"For Palestinian Americans, this is a fundamental issue," sociologist Eman Abdelhadi told Democracy Now! at the march. "We have spent 10 months watching our people die every day, and to ask us to simply just wait and hope that some change will happen... It's just offensive and it's completely insensitive."
As the protesters assembled on Monday, journalist Mehdi Hasan warned in a column in The Guardian that Harris should see agreeing to the demand for an immediate cease-fire in Gaza and an arms embargo not as a risk, but as "a moral, geopolitical, and—for the Democrats—electoral no-brainer."
"Biden may want to continue sending more and more weapons to an Israeli government accused of war crimes at the international criminal court and of genocide at the international court of justice," wrote Hasan, "but Harris should take a different stance—a bolder stance, a stance that is more in line with her party's base, as well as with the American public at large."