For television news aficionados last week, it was all Rick, all the time.

U.S. Sen. Rick Santorum, R-Pa., was on the "Today Show," "Hardball," "The Daily Show," Fox, CNN -- not to mention the KD/PG Sunday Edition.

The chief public appearance for his anticipated challenger, Democratic Treasurer Bob Casey, was an unpublicized stop at a picnic in Erie.

What gives? Why this disparate approach from two members of a profession where publicity is normally valued just behind votes?

The straightforward answer is that Santorum had a book to sell, as he hit the electronic hustings for his newly published polemic, "It Takes a Family.'' But Casey didn't even try to take the spotlight away from his rival. For this, the two sides in what may be the most closely watched Senate race in the nation next year offered competing analyses.

The Casey camp, GOP advisers claim, is trying to hide its candidate, who, while a proven vote-getter, is new to federal issues. His early promising poll numbers, Republicans argue, will wilt as public scrutiny shifts to him from the incumbent.

"I think the motive is obvious,'' said John Brabender, Santorum's media strategist, "I think no one will be in disagreement; they know that the less they take positions on issues, the less they will offend people.''

Casey partisans argue that a better explanation of the current campaign dynamic is that the Democrats see no reason to take the spotlight away from an incumbent who has made a series of polarizing statements in his new book as well as in a three-year-old article on the role of liberal Boston in creating a climate for sexual abuse.

In their view, the failure to compete for the spotlight is in keeping with the political maxim that when your opponent is digging a hole, you should be careful not to take his shovel away.

"I'm sure they'd like to change the subject,'' said Jay Reiff, Casey's campaign manager. "I'm sure they want to talk about anything but the fact that he's writing a book that says that most working moms are self-centered. But we're going to run our campaign our way, we're not going to run it the way they might want.''

This sniping illustrates what promises to be a continuing tactical tension in an unusually intense contest. Elections involving sitting officials are typically referendums on the incumbent. This one, involving a Republican with a national reputation, will be no exception. Throughout the next year and a half, as he did in a concentrated spate of television appearances last week, Santorum will be defending his record. But, taking a page from GOP tactics in the 2004 presidential race, the Santorum campaign is intent on making the contest a referendum on the challenger as well.

In a clear attempt to shape early perceptions on the race, Brabender has peppered reporters in recent weeks with a variation of the question, why is Casey hiding?

Casey, who won his current post with a record number of votes, laughs off the suggestion.

"I don't accept the premise, and I've heard some people advance it, some people from the Santorum camp,'' Casey said as he headed toward the Erie event. "When you've written some of the things that [Santorum's] written, I'm not surprised that they want to change the subject.''

Casey acknowledged that he has not yet issued detailed white papers on a litany of federal issues but says that he's been speaking to those issues since he declared his candidacy in March.

"It's 15 months out; from 18 months out I've been answering questions on the public record. I can't ever remember a candidate, a candidate that wasn't already in the office, answering as many questions as early,'' he said.

Casey said that, even aside from the focus generated by Santorum's book promotion, the nature of their respective offices made it natural for the incumbent to be in a brighter spotlight.

"I'm the state treasurer; I've got work there,'' he said. "He's in the office, the Senate is in session; it's natural that that would drive more coverage.''

"Voters aren't coming up to me and saying, 'Hey you're not answering questions.' '' Casey added. "There's one party running everything in Washington; they have no answers on health care, on the deficit, on a lot of these issues. All they want to talk about is Social Security privatization.''

Previewing some of the issues voters can anticipate hearing more of in coming months, Casey faulted Santorum for what he characterized as a passive attitude toward oversight of the war in Iraq.

"What a lot of Americans want is a whole lot more information than they are getting. They want a senator who is willing to ask tough questions. They want to know where we are on training Iraqi forces, where we are on making sure there is going to be a democracy, on whether our troops have enough armor and the right equipment. I don't think he's asking the tough questions,'' Casey said of the incumbent.

One part of the reason that senior Democrats coalesced behind Casey is that he, like Santorum, opposes abortion, thus negating some of the Republican's potential appeal to socially conservative Democrats. At the time of the Terry Schiavo case, Casey said that he, like Santorum, would have voted for the measure that mandated extraordinary judicial review of whether her feeding tube could be disconnected.

In the interview, however, he signaled that he would not hesitate to criticize Santorum's overall involvement in the case.

"Where there's doubt, you should err on the side of life,'' Casey said, "[but] one thing I would never do, and I don't think any senator should ever have done, is go to that hospice. It was a big mistake. The last thing that site needed, with so much sadness, so much grief, so much, sometimes, hostility, the last thing that site needed was a politician.''

"Let's be clear,'' Brabender said, defending Santorum's widely publicized visit to the Florida hospice. "Nobody sent out a press release saying he was going to visit the Schiavos. Rick went there to say a prayer with them for their daughter. I don't think there's an inappropriate time to pray for a dying family member as Bob Casey evidently does.''

Incumbents often try to ignore their opponents. Challengers, in particular, are typically the supplicants in seeking the joint spotlight of political debates. But Brabender illustrated his intent on switching the focus to this challenger with the unusual suggestion of commencing debates more than a year before the election.

"If Bob Casey has such strong disagreements, how would he feel about starting to debate this fall?'' Brabender said. "If he says that he's not hiding, and he's willing to discuss the issues, let's do two things. Let's start holding debates as early as this fall and let's ask Casey, any time a vote comes up in the U.S. Senate, let's ask him how he would have voted.''

Reiff, the Democrat's campaign manager, professed amusement at his rival's unusual proposal.

"There's a high level of irony here,'' Reiff said, maintaining that Santorum had ducked debates with his 2000 opponent, former Rep. Ron Klink. Actually Klink and Santorum agreed to five debates, but Klink insisted the Republican had spurned his request for still more face-offs.

"Bob Casey will debate, let's be clear.'' Reiff said. "But the fact that an incumbent senator is challenging his opponent to debate 15 months before the election is a sure sign that his campaign is in trouble.''

The proposal comes not only 15 months before the November election, but nearly a year before either figure is the official candidate of his party. While that appears a foregone conclusion for both, it is less of an absolute certaintly for the Democrat.

Last Sunday, about two dozen Democrats and at least one Republican gathered in a condominium on the South Side Slopes to hear Chuck Pennacchio, a history professor at Philadelphia's College of the Arts, make his case for the Democratic nomination. Pennacchio argued that rank-and-file Democrats, particularly those who disagree with Casey on social issues such as abortion and stem cell research, will rebel at the decisions of party leaders to anoint Casey as their candidate.

Alan Sandals, a Philadelphia attorney who similarly favors abortion rights, also has declared his intent to challenge Casey for the party's nomination.

Several of the guests at the Pennacchio reception said they disagreed with Casey's conservative positions on social issues. For similar reasons, many more liberal Democrats had bemoaned former Treasurer Barbara Hafer's decision not to seek the Senate nomination against Casey.

But other Democrats believe the desire to defeat Santorum will outweigh any intra-party disagreements with Casey on individual issues such as abortion.

Marcel Groen, the Democratic chairman of Montgomery County, just outside Philadelphia, said, "The desire to beat Santorum is so great among moderates, that it's not a close call at all. I think the voters in the suburbs realize that. They may disagree with Casey on choice, but they agree on virtually everything else.''

Casey said the preliminary skirmishes of this race reflect the accelerated pace of campaigning in general, but also an unusual degree of national and statewide interest in its outcome.

"We'll both be talking about issues down the road ... I think there's a high degree of interest in this race, an intensity that is rare and a sense that there is so much at stake,'' Casey said. "That's a good thing.''