In the second blow to L.A.’s top labor leadership in less than a year, Los Angeles County Federation of Labor chief Martin Ludlow announced his resignation Tuesday in the face of a mounting scandal over alleged illegal union funding of his 2003 city council campaign.

Ludlow gave no effective date for his resignation, only that it would be “in the near future.” On Thursday, the County Federation of Labor’s 35-member board will meet to consider leadership options, which could include selecting an interim leader and/or launching a search for a permanent successor.

Federal and state investigators have been looking into allegations that the Service Employee International Union Local 99 illegally spent $53,000 to provide cell phones, computers, phone banks and political operatives for Ludlow’s council campaign. If charges are brought and prosecuted, Ludlow could face several years in jail and more than $200,000 in fines and penalties.

Late last week, the Los Angeles Times reported that Ludlow was considering a plea bargain with prosecutors in which he would agree to pay a heavy fine and not to seek or hold public office or union posts for 10 years. The Times reported that prosecutors had given Ludlow until Tuesday to accept or reject the plea bargain.

Ludlow’s sudden resignation appears to close the door on a promising political career for the charismatic 41-year-old, who rose up through union ranks and held several key posts as a political aide before winning the 2003 Los Angeles City Council election.

It also marks the second vacancy at the county’s top labor post in less than a year. Last May, the powerful and widely respected Miguel Contreras died suddenly of a heart attack at the age of 52. Ludlow gave up his City Council seat to replace Contreras. Ludlow’s former boss in the state Assembly, Herb Wesson, ran against token opposition to win election last year to replace Ludlow on the Council.