Two union leaders and longtime Democratic National Committee members have resigned from the national party, marking the latest internal dispute of chairman Ken Martin’s tenure.

In her resignation letter, Randi Weingarten referenced her disagreements with Democratic National Committee Chairman Ken Martin's leadership as a reason she couldn't continue as one of the organization's leaders.

Randi Weingarten, head of one of the nation’s most influential teachers unions, and Lee Saunders, the president of a large union of public workers, each pointed to Ken Martin’s leadership.