Some Democrats had hoped to act on the issue before their party loses unified control of Congress, but a lack of political will and time appears to have sapped momentum for doing so.
The decision by the Maryland Democrat, who has served in Congress for four decades two of them in leadership reflected a generational and demographic shift afoot in his party.
A new trio, including Representatives Katherine Clark of Massachusetts as No. 2 and Pete Aguilar of California as No. 3 will take the reins in January, replacing Speaker Nancy Pelosi and her team.
The first and only female speaker of the House, Nancy Pelosi announced that she would step down from leadership in January but would remain in Congress.