Name: Joe Sestak
Age: 58
Home: Delaware County
Experience: Congressman and former Navy admiral
Website: http://joesestak.com/Home/Home.html

Rep. Joe Sestak is risking his brief, bright political career bucking the state’s longest serving senator as well as the leadership of his own party.  Mr. Sestak, a retired U.S. Navy admiral, is trying to wrest the Democratic nomination from Mr. Specter, arguing that the incumbent is an ideological question mark.  True Democrats, he contends, can’t count on Mr. Specter’s vote any more than Republicans could.  Mr. Sestak has portrayed himself as the outsider’s candidate, hoping to capitalize on the anti-incumbent sentiment of recession-battered voters.

He captured his suburban Philadelphia House seat in 2006, ousting a veteran Republican.  Early polls haven’t shown him making much headway against Mr. Specter.  But that could change fast.  Mr. Sestak is sitting on more than $5 million in campaign cash, meaning that he has the resources to raise his name ID quickly as the primary enters its home stretch. On one tactical level, this race will be a referendum on the incumbent.  But another component of the competition will be a race to define Joe Sestak to voters who hardly know him.

Name: Arlen Specter
Age: 80
Home: Philadelphia
Experience: Five-term senator and former prosecutor
Website: http://www.specter2010.com

Arlen Specter, the state’s longest serving senator, the great survivor of Pennsylvania politics, may face his toughest test this year.  His stunning shift from Republican to Democrat last April gave his new party a temporary filibuster proof majority in the Senate.  But his switch was rewarded with an energetic challenge in the primary of his new party, from Rep. Joe Sestak, a retired admiral from Delaware County..  If he survives that, he will face a familiar opponent in November -- former Rep. Pat Toomey, the conservative Republican who nearly ousted him in the GOP’s 2004 primary.

To survive once again, Mr. Specter is relying on the strengths of incumbency and his decades of cultivating support with regular visits in each of the state’s 67 counties.  Mr. Specter also has the support of the Democratic hierarchy including President Obama, Vice President Biden and Gov. Ed Rendell, his former aide in the Philadelphia district attorney’s office.

Name: Peg Luksik
Age: 54
Home: Cambria County
Experience: Activist and former gubernatorial candidate
Website: http://pegluksik.com/

Peg Luksik, a conservative activist from Johnstown, shocked the state’s political establishment in 1990 when she nearly won the Republican nomination for governor. Her showings were less impressive in the next two gubernatorial elections, when, running as an independent, she twice finished a distant third.  Her candidacies as the nominee of the Constitutional Party weren’t major tactical factors in either election.  She’s remained politically active since, as a columnist and occasional radio and television commentator on conservative issues. 

Both she and her rival, Mr. Toomey, describe themselves as conservatives but Mrs. Luksik’s focus has been directed more toward social issues, notably her opposition to abortion.  A multi-tasker, she is also managing the congressional campaign of Republican William Russell the Republican primary for he 12^th Congressional District, a role she played in 2008 as well.  Mrs. Luksik has had little success in fund-raising, but she contends that her grass-roots network, abetted by her appeal to new Tea Party and 9.12 activists, will produce a surprise on May 18.

Name: Pat Toomey
Age: 48
Home: Lehigh County
Experience: Former banker, congressman and activist
Website: http://www.toomeyforsenate.com/

Rep. Pat Toomey nearly defeated Sen. Arlen Specter six years ago, falling just short of capturing the Republican nomination.  As 2009 opened, he was giving some thought to running for governor. But that was before Mr. Specter voted to support the Obama administration’s massive recovery package.  Now the GOP state leaders who scorned him in favor of Mr. Specter in 2004 are solidly behind his candidacy. 

A former president of the Club for Growth, he earned a reputation as a budget hawk during his years representing a Lehigh Valley congressional district.  His campaign believes that brand of fiscal conservatism will appeal to an electorate increasingly concerned about rising deficits.  Balancing his conservatism, he has looked for opportunities to reach across party lines, having beers with Joe Sestak and tempering his general criticism of the Obama administration with occasional praise on issues such as trade.