Ms. Purcell, a Republican holding the office since 1988, tried to offer explanations for what went wrong as the county reduced the number of polling places to 60 from 200 — one site for roughly 21,500 voters — but the capacity crowd was having none of it.

One man said, “Not good enough.” The audience cheered.

More than 100 voters filled three interconnected rooms, and more than 30 signed up to testify. Security personnel stood on the sides, and at one point a handful of state troopers moved inside, threatening to remove anyone who was disruptive.

The hearing ended in mid-session at 1:30 p.m. because committee members had to move to another hearing to vote on a campaign finance bill. One of the members, Ken Clark, a Democrat, urged audience members to follow them, and they did. A masked man screamed from the gallery; troopers soon surrounded him and took him outside in handcuffs, delaying the hearing’s start.

Ms. Purcell had already said that her office would make new plans for November, presumably adding more polling sites.

Meanwhile, Michelle Reagan, the Arizona secretary of state — who told reporters before the hearing that she had known about the cutback in polling places, but had not wanted to “second-guess” the county’s decision — said she planned to hold four community meetings in the areas most affected by the long lines, all but one in heavily Hispanic parts of the county.