George Matta is facing a petition challenge too, which could prove more serious than the one he filed against county controller opponent Chelsa Wagner.

The challenge against the former clerk of courts and current Rivers Casino employee is simple: when candidates photocopy petitions the copies must be exact, and Matta's added a union label to the bottom right corner. That not only violated election law but incorrectly implied a union endorsement, the challenge says. (Wagner, a state Rep from Brookline, won the Allegheny County Labor Council nod.)

From the challenge:

Matta has challenged fellow Democrat Wagner's petitions, saying she was out of town when she circulated one of the signature forms. They and Valerie McDonald Roberts are running for the Democratic nomination for the county controller seat.

UPDATE: Infinonymous indicates Wagner could be in real trouble, as a check of her petitions indeed shows she didn't sign/notarize the back page of most of her affidavits. Armstrong County's Chuck Pascal is serving as her lawyer in the matter.

Many other challenges were filed yesterday, many of them in small municipal races. Bigger Pittsburgh-centered races included challenges to:

-- District 1/North Side city council candidates Steven Oberst and Bobby Wilson. Challenges alleged 46 of Oberst's 140 signatures were bad (100 are needed) and that he lives in Ross Twp, whereas the Wilson challenge says his mother violated the Notary Public Law by being his notary.

-- District 3/South Side city council candidate Jason Phillips filed only 118 signatures, and 34 of them are bad for one reason or another, states a challenge handled by attorney Lisa Michel.

Michel also filed the challenges against Oberst and Wilson, leading one to suspect she is helping clear up the field for District 1&3 challengers Vince Pallus and Jeff Koch, who both were endorsed by the county Democratic committee and have the backing of the Ravenstahl administration. (The incumbents in those seats are mayoral critics Darlene Harris and Bruce Kraus.)

Another interesting note for Pgh politics junkies: a look at Phillips' petitions shows they were notarized by former councilman and current District Judge Gene Ricciardi.

Finally, Squirrel Hill Republican Josh Wander -- who is running for both city council District 5 spot and Rich Fitzgerald's former county council District 11 seat -- had his county petitions challenged, in a complaint claiming that enough of his 296 signatures are bad (of the 250 needed for the seat) that he should be tossed from the county ballot.

Can't get enough? Court hearings on the challenges will start in the (crowded, by the looks of it) courtroom of Judge Joe James starting next Wednesday.