The Rev. Al Sharpton will not endorse a candidate for the Democratic mayoral nomination, sitting out the primary for first time in 20 years because the candidates have thus far failed to present a clear message or a winning strategy, he said yesterday. Mr. Sharpton held open the possibility that if the situation changed, he might make an endorsement in August, just before the primary. An associate said that he had been prepared to make an early endorsement of Fernando Ferrer but that that had changed after Mr. Ferrer told a police union that he did not think the fatal police shooting of Amadou Diallo, an unarmed African immigrant, was a crime. "I was personally troubled by Mr. Ferrer's statement," Mr. Sharpton said in an interview in his Midtown office, accompanied by Marjorie Harris, a senior adviser. "Part of our career has been to deal with the criminalization of police brutality, and one statement implied that he did not agree with the criminalization and that is something that's very serious to me." Mr. Sharpton supplied pivotal support to Mr. Ferrer in 2001 after lengthy deliberations, and the Ferrer campaign was hoping for his support this time around as it sought to build a black and Hispanic coalition to win the Democratic nomination, but the Diallo matter led to an outcry against Mr. Ferrer among black leaders. In helping him make the decision, Mr. Sharpton said, Ms. Harris consulted with members of Mr. Sharpton's political organization throughout the city and found that there was some support for C. Virginia Fields, the Manhattan borough president and the only black candidate in the race. But, they said, it was not enough to justify an endorsement. "I think to endorse without being convinced of the absolute positions that people are running on combined with a winning strategy would be to cheapen and trivialize what we've tried to build in this city," Mr. Sharpton said. [more]