You probably saw last week's independent poll showing that if the 2006 race for U.S. senator in Pennsylvania were held now, Democrat Robert P. Casey Jr., the state treasurer, would trounce Republican incumbent Rick Santorum by 14 points. But a lot has to happen between now and November 2006.

A campaign, for example.

Santorum is already running, and, in fact, has never really stopped. Whether he's rushing to Florida to pray with Terri Schiavo's parents (Would Jesus have prayed with her husband, too?); flacking for George Bush's privatized Social Security accounts (The brokerage houses are licking their chops over that one); or privatizing the weather ("That rain out there is just a liberal plot to keep you from going to Wal-Mart; in fact, it's sunny and 75 degrees!"), the third-ranking Republican in the Senate knows how to raise money, grab headlines and curry favor with corporate honchos and the religious right.

Casey, on the other hand, has yet to say or do much in the way of a senatorial campaign. Of course, it's still early -- technically he still has to win the nomination in next May's primary. But Gov. Ed Rendell last month made him look like a shoo-in when he persuaded Barbara Hafer to withdraw and threw his backing to Casey.

Still, if he's going to snatch the Senate seat from a two-term incumbent with a national fund-raising pool, Casey hasn't a moment to spare. His name alone won't win the day. Voters who sent his dad to Harrisburg for two terms as governor still want to hear what the son would hope to accomplish in Washington.

As state auditor general he styled himself as a protector of the public interest and a thorn in the side of Republican Gov. Tom Ridge, but there's no way of knowing how any of that would translate from the state capital to the Capitol.

In announcing, Casey cited trade, health care and Social Security as central issues. He did not mention the hot-button social issues that can cut both ways in political campaigns. But sooner rather than later, he's going to have to face those things head-on.

Casey is like Santorum in that both are selective "pro-lifers" who oppose abortion and favor the death penalty. That both helps and hurts them in Pennsylvania, where conservative Democrats and moderate Republicans have a tradition of voting across party lines.

Rendell's abortion rights stand helped him win support from liberals and moderates in both parties. Ditto for John F. Kerry, who defeated President Bush in Pennsylvania. Then again, Casey's father won with the help of social conservatives of both parties -- and so did Ronald Reagan.

How is Casey going to finesse these issues? The answer: He's not. If he's to win, it'll be where he and Santorum differ.

Casey, says campaign manager Marc Farinella, wants a "real strengthening of Social Security," not "massive borrowing from overseas, cutting benefits and other things that do nothing to dress long-term solvency." He opposes the cuts to Medicare and Medicaid that Bush and Santorum favor; he wants to see a "meaningful prescription drug program." He feels that Santorum and Republicans "have turned their backs on middle-class families, and he opposes Republican efforts to eliminate the filibuster. He also opposes gay marriage but supports civil unions.

As to which judges Casey would vote to confirm, Farinella offers the standard evasion: independent review and "no litmus test."

If he expects to win over voters who want a more liberal opponent to Santorum's hard-line conservatism, Casey will have to offer a lot more than that. The election is only 18 months away. He'd better get started.