If he is given the unified support of his party, state Treasurer Bob Casey Jr. could be U.S. Sen. Rick Santorum's worst nightmare. The Democrat has strong name recognition, not only as the son of a famous and much-loved governor but also in his own right by reason of a distinguished career of public service.

Mr. Casey, 46, of Scranton is a proven vote-getter. When he was elected treasurer in 2004, he won more votes than any other candidate for state or federal office in the history of Pennsylvania. Before that, he was elected statewide as auditor general in 1996 and re-elected in 2000. His one statewide loss was in the Democratic gubernatorial primary in 2002, which was won by Ed Rendell and did Mr. Casey no lasting damage or shame.

Bob Casey also has the potential to cause problems for Sen. Santorum among the Republican's base. As with his father before him, Mr. Casey opposes abortion, a stand that could siphon votes away from Sen. Santorum or at least give conservatives feeling neglected by him an excuse to stay home in the November election.

That, of course, is also a problem for Mr. Casey at the other pole. Some Democrats were annoyed that party leaders, including Gov. Rendell, asked the pro-choice Barbara Hafer not to run for the Senate in the interests of improving Mr. Casey's chances.

For those still nurturing that grudge and wanting the means to express it, two other Democrats are contesting the primary. They agree with Mr. Casey in some particulars but their brand of liberal politics is to the left of the front-runner. On the subject of a woman's right to choose, both are in the pro-choice camp (as is the Post-Gazette editorial board).

Alan Sandals, 52, of Philadelphia is a lawyer who graduated from the University of Pennsylvania law school and who takes pride in representing working people in a practice specializing in pensions and medical benefits.

Chuck Pennacchio, 46, of Bucks County has a doctorate in American, European and diplomatic history and teaches at the University of the Arts in Philadelphia. He is a former aide to U.S. Sen. Alan Cranston, worked for U.S. Rep. Ron Dellums on military personnel issues and helped in several Senate campaigns.

Neither of these two candidates has held public office before and both have unrealistically optimistic views of their chances. In the event of a minor miracle in the primary, neither man could hope for a major miracle head-to-head against Sen. Santorum. They could not straddle the middle as Mr. Casey can. They do not have the experience or the name recognition -- and they won't have the money.

Mr. Casey himself is likely to be outspent by Sen. Santorum, but he has a sterling record in office to draw upon. Those Democratic voters still hung up on a litmus test should consider that Mr. Casey is not one of those pro-lifers whose concern for the unborn stops at birth. His compassion extends to those living and breathing people -- among them women, children and seniors -- who need a helping hand. His whole record in office and on the campaign trail speaks to his commitment to fiscal responsibility, encouraging good jobs, protecting the environment and restoring sanity to American foreign policy.

Democrats have choices in this primary, but they should rally behind the best candidate in this race, Bob Casey Jr.