The Democratic Caucus selected its leadership slate Thursday, affirming its commitment to Minority Leader Nancy Pelosi of California and her top lieutenants in elections that had been largely determined weeks ago. But the caucus now faces the task of filling the key spot of Appropriations ranking member, for which Reps. Nita M. Lowey of New York and Marcy Kaptur of Ohio are waging a closely fought race.

The position is open because Rep. Norm Dicks of Washington is retiring. Normally the party defers to seniority for committee slots, although it has made exceptions, most notably in 2009 when Rep. Henry A. Waxman of California wrested the gavel of the Energy and Commerce Committee from Rep. John D. Dingell of Michigan, largely with Pelosi’s blessing.

Going by seniority, Kaptur would ascend to the top spot on the panel, where she’s served for 22 years. But she has a couple of limiting factors: She is a consistent opponent of expanding abortion rights and in the past has had a rocky relationship with Pelosi.

In 2010, Kaptur and Rep. Peter A. DeFazio, D-Ore., urged Pelosi to postpone leadership elections after she surprised Democrats with her intentions to stay on as leader. And Kaptur’s abortion position was a roadblock during consideration of the health care overhaul.

Kaptur met with Pelosi for 30 minutes Tuesday, and the minority leader said she was neutral in the race, according to Steve Fought, Kaptur’s communications director.

Lowey is third in seniority on the panel and fits more neatly into leadership, with her past tenure leading the Democratic Congressional Campaign Committee. She asked for support Wednesday in a letter to colleagues, touting her past work as DCCC chairwoman and saying she is a good fit for the current atmosphere of partisan spending showdowns.

“I have a record of working across the broad spectrum of our Caucus to build consensus on challenging issues, including many that Republicans often inappropriately add to appropriations bills,” Lowey wrote.

Her camp is expressing optimism about the New York lawmaker’s standing in the race, while Fought described the contest as “up for grabs.”

In a Nov. 16 letter, Kaptur defended her role in the passage of President Barack Obama’s 2010 health care law as it relates to abortion. Then, she fought to prevent the law from providing government funding for abortions.

“I am aware of distortions of my positions on women’s health issues and abortion, some of them stemming” from that episode, Kaptur wrote to her colleagues. “I support Roe v. Wade unconditionally,” she said, adding, “In my position as Ranking Member, I will stand against the Republicans in their attempts to needlessly inject abortion policy riders into the Committee’s work.”

The Democratic Steering Committee is expected to make recommendations soon but has not scheduled a meeting yet.