Like so much in Iraq these days, the issue goes back to the earliest days of the American occupation, when L. Paul Bremer, the administrator of Iraq, outlawed the party in May 2003 and in November that year started a commission to oversee what was known as de-Baathification, barring all but the party’s junior members from public life.

In Arabic, the word for it, ijtithath, was far stronger, meaning to uproot or tear out.

The Accountability and Justice Commission, while on shaky legal grounds, has served as its successor, though it remains no less contentious. The man in charge of the disqualifications, Ali Faisal al-Lami, is a close aide to Ahmed Chalabi, once a confidant of the Bush administration in the preparations for the war. Mr. Lami has close ties to Iran and was suspected in the murderous activities of Shiite militants  charges that he denies.

Confusing matters, he, like Mr. Chalabi, is a candidate, vetting other candidates.

Mr. Lami dismissed the notion that the process he oversaw was in any way politicized. He maintained that the commission faithfully carried out Iraq’s de-Baathification laws, eliminating candidates who were on the commission’s databases of former members of the party, or Iraq’s security forces. If the disqualifications resulted in feelings of disenfranchisement, he said, it was the fault of the law, not his commission’s work. But critics view the charges of promoting the party as merely a tool to eliminate secular opponents of Iraq’s Shiite religious parties who stood to fare well in the March 7 vote. Many say the breadth of the disqualifications has underlined how far Iraq remains from resolving the question of precisely what national reconciliation means.

Mr. Hashemi called the ban “dangerous.” “Those barred candidates,” he said after meeting the British ambassador, “had become partners in the political process and accepted its terms and standards.”

Perception has long guided events here, often shaped by sectarian and ethnic identities and the narratives that construct them. For many Shiites and Kurds, Baathist remains a chauvinistic term that connotes the genocidal campaign against Kurds at the end of the 1980-88 Iran-Iraq war and the mass graves filled after the 1991 Persian Gulf war.

While opinions vary widely, the party still enjoys support in Sunni regions, some of it expressed in affection for Mr. Hussein himself. In Anbar Province, he is often idealized as a nationalist figure who stood against Iran and savagely repressed religious parties. Even opponents of Mr. Hussein see the term Baathist as coded language.

“We need a definition for the word,” said Mr. Mashhadani, the spokesman for Mr. Sammarai. “Who’s a Baathist? What is a Baathist?”