Representative LaMonica McIver, a New Jersey Democrat, on Wednesday overcame a Republican-led effort to punish her for her role in a clash outside a migrant detention center in Newark that has become a hub of protest over President Trump’s deportation policies.

Ms. McIver, 39, was charged in May with assaulting and interfering with Immigration and Customs Enforcement agents after a confrontation involving the city’s mayor, Ras J. Baraka.

She has pleaded not guilty. And on Wednesday afternoon seven Republicans joined with Democrats to block a resolution that would have led her to be censured and removed from the Committee on Homeland Security.

Ms. McIver, a first-term House member from Newark, was outside the detention center on May 9 when agents, wearing masks and camouflage gear, moved in to arrest Mr. Baraka on trespassing charges, leading to a volatile scrum. Video showed her pushing toward the gates and being pushed from behind after Mr. Baraka was handcuffed.

Ms. McIver was there for a House oversight visit and, immediately after the incident, was invited into the facility and led on a tour with two of her Democratic colleagues, Representatives Bonnie Watson Coleman and Rob Menendez.

Ten days later, Alina Habba, New Jersey’s top federal prosecutor, announced in a news release that she was dropping the trespassing charge against Mr. Baraka — but would pursue charges against Ms. McIver. A grand jury later handed up an indictment that accused Ms. McIver of “forcibly grabbing” one agent and “using her forearms” to strike a second agent as she sought to block the mayor’s arrest.