Randi Weingarten of the American Federation of Teachers and Lee Saunders of AFSCME, declined offers to stay on. Weingarten cited disagreements with Martin.

They expressed frustration over the DNC’s break-up with American Federation of Teachers President Randi Weingarten and AFSCME President Lee Saunders — who between them represent millions of members — as the latest sign of a widening gap between party leadership and the labor movement, a once-core part of the Democratic coalition.

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.