PHOENIX – The showdown over Arizona’s immigration law played out in court and on Phoenix’s sun-splashed streets on Thursday, as the state sought to reinstate key parts of the measure and angry protesters chanted that they refused to “live in fear.” Dozens were arrested.

A federal judge’s decision a day earlier to block the strict law’s most controversial elements didn’t dampen the raging immigration debate.

The judge has been threatened. Protesters rallied in cities from Los Angeles to New York. The sheriff of the state’s most populous county vowed to continue targeting illegal immigrants.

In Phoenix, hundreds of the law’s opponents massed at a downtown jail, beating on the metal door and forcing sheriff’s deputies to call for backup. Officers in riot gear opened the doors, waded out into the crowd and hauled off those who didn’t move. They arrested at least 23 people, and more were detained elsewhere.

Activists focused their rage at Maricopa County Sheriff Joe Arpaio, the 78-year-old ex-federal drug agent known for his immigration sweeps.

Outside his downtown office, marchers chanted “Sheriff Joe, we are here. We will not live in fear.” One was dressed in a papier-mache “Sheriff Joe” head and prison garb.

“I’m not going to be intimidated and stopped,” Arpaio said.

Activists, armed with video cameras and aided by others listening to police scanners, roamed the county’s neighborhoods, saying they were ready to document any deputies harassing Hispanics.

Since Wednesday’s ruling, U.S. District Judge Susan Bolton has received thousands of phone calls and e-mails. Some were positive, but others were “from people venting and who have expressed their displeasure in a perverted way,” said David Gonzales, the U.S. marshal for Arizona.

In her temporary injunction, Bolton delayed the most contentious provisions of the law, including a section that required officers to check a person’s immigration status while enforcing other laws.