The dustup began after Crenshaw reacted to comments made by Rep. Ilhan Omar, D-Minn., who had been criticized for characterizing the 9/11 terrorist attacks as "some people did something."
"First Member of Congress to ever describe terrorists who killed thousands of Americans on 9/11 as 'some people who did something.' Unbelievable," Crenshaw tweeted.
That prompted Ocasio-Cortez to defend her Minnesota ally, going after the Texas congressman for not co-sponsoring the 9/11 Victim's Compensation Fund.
"In 2018, right-wing extremists were behind almost ALL US domestic terrorist killings. Why don't you go do something about that?" Ocasio-Cortez told Crenshaw.
That sparked an avalanche of outrage, many pointing to Crenshaw's service as a Navy SEAL in the war in Afghanistan as well as his sacrifice.
Crenshaw did not immediately respond.