Rep. Sander M. Levin of Michigan will step down as the top Democrat on the House Ways and Means Committee at the end of this year, opening a position atop one of the most powerful committees in Congress as Democrats seek to combat the agenda advanced by President-elect Trump and congressional Republicans.

Levin, who has been the top Democrat on the committee since 2010, informed colleagues of his plans on Tuesday in a letter, a copy of which was obtained by The Washington Post. His decision to not seek reelection adds a new opportunity for a fresh face to join House Democrats’ top ranks amid frustration over the party’s disappointing election showing.

“It is imperative that we support younger Members as they seek to fully assume the mantle of leadership in the four years ahead, as we also continue to tap the experience of those who have led so many of these battles,” Levin wrote.

Levin’s vacancy sets up a showdown between Reps. Xavier Becerra (D-Calif.) and Richard E. Neal (D-Mass.) over who will be the panel’s top Democrat. Becerra, a close confidant of House Minority Leader Nancy Pelosi (D-Calif.) and a member of the Congressional Progressive Caucus, will leave his position as chairman of the House Democratic Conference at the end of this year. Neal, who challenged Levin for the ranking member slot in 2010, is a well-liked more moderate member with close relationships with many of the younger House Democrats.

Becerra and Neal both confirmed Tuesday their plans to run for ranking member.

“I’m going to work hard on the committee,” Becerra said.

Asked if he had the necessary support to get the slot, he smiled and said: “That’s why I’m going to work hard.”

Neal told reporters he was confident that he will get strong support from his colleagues.

“My hunch is I will do very well with members on the Ways and Means Committee,” Neal said. “In fact, I would guess I would have a substantial majority.”

The showdown comes as House Minority Leader Nancy Pelosi (D-Calif.) and her allies are aggressively campaigning to defend her leadership against Ohio Democrat Tim Ryan’s insurgent bid to unseat her as minority leader.

Democrats are scheduled to choose their party leaders on Wednesday morning and it is unclear if Ryan can sway enough members to threaten Pelosi’s position.

Younger members are frustrated that Pelosi and her allies have maintained tight control over committee slots and leadership positions for years and they are pushing for greater opportunities to influence the party’s direction and message. Pelosi has taken some steps to offer positions to younger members, but Ryan’s allies have so far not been satisfied by the moves.

The Ways and Means Committee has been seen by many Democrats as a powerful committee where young members have very little chance of gaining influence. The youngest member on the panel is Rep. Linda T. Sánchez (D-Calif.), 47, who was just elected to her eighth term. Levin, 85, was first elected to Congress in 1982.

The top spot on Ways and Means promises to be an important perch for Democrats in the first years of the new Trump administration. The committee will lead the effort to lower tax rates and overhaul the tax code and will also likely play a role in plans to repeal the Affordable Care Act and to boost infrastructure projects across the country.

Levin’s decision to step down was welcomed by some Ryan allies, but Rep. Ruben Gallego (D-Ariz.) said broader changes are still needed within party ranks.

“Movements like this are appreciated but they don’t get to the core of the problem,” Gallego said.

Ed O’Keefe contributed to this story.