For the ‘Squad,’ a Split-Screen Existence In and Out of Congress

New progressives Omar, Ocasio-Cortez, Pressley and Tlaib attracted celebrity-like attention even before they became representatives; in the House, they have frequently rankled colleagues.

WASHINGTON—After weeks in the news because of her disputes with Speaker Nancy Pelosi and being on the receiving end of insults from President Trump, Rep. Ilhan Omar marched out of the Capitol Thursday afternoon, bringing traffic to a halt on Independence Avenue by the Mall, and told a gaggle of reporters not to stampede a photographer who fell in the melee.

“For the sake of a story, don’t kill each other,” she said.

As members of Congress go, Ms. Omar (D., Minn.) and the other three Democratic members of the self-described “squad” of new progressives already were celebrities for the impact they made when they arrived in Congress in January. She, with Rashida Tlaib of Michigan, Alexandria Ocasio-Cortez of New York and Ayanna Pressley of Massachusetts met at a media interview in freshmen orientation and when Ms. Ocasio-Cortez posted a photo of the four on Instagram with the caption “squad,” the name stuck.

Since then, however, they have led a split-screen existence in the Democratic Party, inside and outside Congress.

In the chamber, they have frequently rankled colleagues and stolen the spotlight with their controversies and they have been in a long-running dispute over priorities with Mrs. Pelosi, with Ms. Ocasio-Cortez recently suggesting that the speaker was singling them out as people of color. She also compared southern border detention centers to concentration camps.