Rep. Joe Sestak is trying to have an Allegheny County opponent thrown off the ballot. The Onorato campaign considered asking a court to do the same thing with a gubernatorial contender, but changed its mind. And the only woman on the crowded GOP lieutenant governor's ballot faces an early threat to her candidacy.

It's all part of the political rite of spring, when candidates take a political magnifying glass to their rivals' nominating petitions, hoping to find some flaw in signatures or required disclosures that will allow them to short-circuit their foes' campaigns.

Mr. Sestak, who is challenging Sen. Arlen Specter for the Democratic nomination, moved against the late emerging challenge of Robinson's Joseph Vod Varka, a retired machinist waging his own populist bid for the Senate seat. The Sestak campaign contends that he didn't get enough valid signatures to qualify his candidacy.

It might seem like political overkill for Mr. Sestak to worry about the little-known, underfunded candidate, but he could conceivably be a threat to the Sestak challenge by competing for generic anti-incumbent votes on May 18.

Mr. Onorato's lawyers initially challenged Joe Hoeffel's petitions. Before the day was over, however, they withdrew the challenge. Behind the maneuvering was a little gamesmanship in the four-candidate Democratic race. The Onorato forces anticipated that the Hoeffel campaign might challenge the petitions of yet another candidate -- Philadelphia's state Sen. Anthony Hardy Williams. If that happened, the Onorato campaign wanted to avoid the possibility that Mr. Hoeffel would emerge as the sole surviving southeastern candidate against Mr. Onorato and his Allegheny County neighbor, Auditor General Jack Wagner.

When it became clear that Mr. Hoeffel would not challenge Mr. Williams, they then saw no need to challenge Mr. Hoeffel.

Another statewide candidate, Erie's Jean Craige Pepper, is the only woman in the crowed, nine-person field for the GOP nomination for lieutenant governor. She is also the target of a challenge.

In Allegheny County, several legislative candidates' petitions are facing scrutiny for a variety of reasons. In the 20th Legislative District, three challenges have emerged among the five candidates Democratic field. A voter named Karen McCue filed challenges against Adam Ravenstahl, Mayor Luke Ravenstahl's brother, contending that he did not properly list debts on a financial disclosure form. Mr. Ravenstahl issued a statement insisting the challenge had no merit.

Ms. McCue is also challenging another 20th District Democrat, Dan Keller, claiming that his nomination papers were flawed because he didn't list his membership on the board of Alcosan. Mr. Keller said that since the position is unpaid, he did not believe it fell under the disclosure rule. Another 20th District contender, Timothy H. Tuinstra, is challenging the signatures of the remaining contender, Frank M. Machi Jr.

In another House contest in the county, Rep. Nick Kotik, D-Robinson, is challenging the petitions of his Democratic primary challenger, Maribeth Taylor.

In the 3rd Congressional District, in the Northwest corner of the state, incumbent Democrat Kathy Dahlkemper faces a petition challenge from a Democratic challenger, Mel Marin.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.