John Dougherty, leader of Local 98 of the electricians' union, began circulating nominating petitions last weekend for a possible challenge to State Sen. Vincent J. Fumo in the April 22 Democratic primary.

The move raises the spectre of a showdown between two powerful politicians whose clashes have become part of local lore.

Yesterday, the speculation was about whether Dougherty seriously intended to challenge Fumo for his First Senatorial District seat, or was simply taking a preemptive action should the senator decline or be unable to seek reelection because of his legal problems.

Fumo faces trial next month on federal charges that he misused Senate staff and two charities for personal and political gain.

If both Dougherty and Fumo appear on the ballot, it would be the first time they had gone head to head before voters.

Their battles have been by proxy, contests in which each man has supported a rival candidate. For instance, City Councilman and Fumo ally Frank DiCicco was unsuccessfully challenged by Vern Anastasio, who in the past has received financial backing from Dougherty's union.

Dougherty is a third possible contender for the South Philadelphia district, as political activist Anne Dicker already has stated her intention to run. Another challenge might come from former City Councilman and Controller Joseph C. Vignola.

Dougherty could not be reached for comment yesterday. But he spent part of the day making telephone calls to tell political officials, including Councilman Bill Green, what he was doing.

"Yes, he called," Green said. "He said he was circulating petitions."

Nominating petitions are due Feb. 12. Candidates then have until Feb. 27 to withdraw from a race.

Contact staff writer Marcia Gelbart at 215-854-2338 or mgelbart@phillynews.com.