In what could be his most important endorsement in the tight Senate primary, Michigan's largest and most influential union said El-Sayed was "someone we can trust to have our backs."

El Sayed’s support has surged among Democratic voters over the past several months, allowing him to lap his opponents by double digits in a recent survey.

In what could be his most important endorsement in the tight Senate primary, Michigan's largest and most influential union said El-Sayed was "someone we can trust to have our…