Last Thursday D.C. Mayor Anthony Williams finally ended the speculation as to his plans for 2006 — he announced he would not run for a third term. But while his decision finally provides some clarity for the current crop of mayoral contenders — they no longer have to live with the election-altering specter of Williams vying for the job again — it also provides the current mayor the powerful opportunity to endorse a successor.

The power of endorsement — especially in a city whose next mayor will only be the fifth elected mayor since home rule was established in 1975 — will carry both benefits and liabilities for the candidate who receives it. As the Post noted both in its reporting and editorializing, Williams will leave office next year with a record of being an effective manager whose policies brought financial sanity to the city while alienating some of its poorest residents. Whoever receives his endorsement will have to skillfully exploit the goods while promising to correct the bads — all while avoiding the appearance of being a Williams suck-up or criticizing him too harshly. And while a source in the mayor’s office informed us that Williams will not announce any endorsements until early next year, speculation is in order.