As the Democratic Party struggles to broaden its electoral appeal, the issue of abortion has stolen a leading role not only in the party’s search for a new leader but also in what is expected to be one of this cycle’s premiere Senate races.

While it remains to be seen whether former Rep. Tim Roemer (Ind.), who opposes abortion rights, will ascend to the chairmanship of the Democratic National Committee early next month, party leaders are also in the process of wooing a candidate with similar views into the race against Sen. Rick Santorum (R-Pa.) in 2006.

Pennsylvania state Treasurer Bob Casey Jr. (D), the namesake of the late popular former governor once shunned by the national party because of his abortion beliefs, is widely being billed as the strongest potential challenger to Santorum, a darling of religious conservatives.

Both Senate Minority Leader Harry Reid (D-Nev.), who also does not support abortion rights, and Democratic Senatorial Campaign Committee Chairman Charles Schumer (N.Y.) — who does — have already reached out to Casey to encourage him to run.

“You have liberals and pro-choice people excited about Bob Casey,” said Larry Ceisler, a Philadelphia-area Democratic consultant. “They want to a) defeat Rick Santorum and they want to b) win the White House back in four years, and they just feel that the party has to be more inclusive.”

The recruitment of Casey is a significant sidelight in the Democratic Party’s ongoing struggle to regroup after across-the-board defeats in last year’s presidential and Congressional elections.

Casey is unlikely to get in the race unless the Democratic field is cleared of any major opposition, including pro-abortion rights contenders. Other Democrats who have expressed interest in the Senate race include former Rep. Joe Hoeffel, who lost to Sen. Arlen Specter (R) last year, and former state Treasurer Barbara Hafer, an ex-Republican. Both support abortion rights.

Casey, 44, has solid statewide name identification. Formerly the state auditor, he was just elected treasurer in November with more than 3.3 million votes, more than any other candidate in state history.

But perhaps Democrats are most encouraged about Casey as their candidate because two of the most explosive social issues — guns and abortion — would be taken off the table in a race against Santorum.

“He neutralizes Santorum on a couple of Santorum’s big issues,” said a Democratic campaign strategist. “He packs a powerful punch.”

But not all Democrats believe that Casey would be the party’s strongest nominee. With the memories of Santorum’s last re-election campaign still painfully fresh in their minds, some in the party are taking a “been there, done that” attitude and quietly urging leaders to move in another direction.

“You don’t beat Santorum by putting up somebody pro-life and pro-gun against him,” said another Democratic consultant in the state. “That’s not how you beat him last time. And I believe that you don’t beat him this time by doing that.”

In 2000 Democrats nominated then-Rep. Ron Klink, an abortion rights foe from Santorum’s same base in the western part of the state. While Klink’s candidacy looked good on paper, his campaign never gained much traction as he struggled to replenish his coffers after the primary.

Santorum eventually won a second term with 52 percent of the vote, even as then-Vice President Al Gore won the state in the presidential contest by 5 points. Santorum spent more than $10.5 million, compared to Klink’s $3.6 million on the race.

The consultant argued that Casey might find similar money troubles in a race against Santorum because the party’s liberal donor base in Philadelphia, as well as progressives nationally, are less likely to give enthusiastically to a anti-abortion, pro-gun rights Democrat.

“In this state I think you only have the potential of taking out a candidate like Santorum if you run somebody that is clearly differentiated from Santorum on the social litmus test issues,” the consultant said. “It’s not just about political profile, it’s about money.”

Santorum is considered one of the top targets for Democrats in the 2006 cycle. That fact alone, some Democrats say, will help drive the fundraising efforts of his opponent, regardless of who it is. And if, as expected, a high-profile battle over a Supreme Court nomination unfolds in the next two years, an unprecedented amount of money could flow to both sides of the Pennsylvania Senate race.

“Santorum is a lot like the D’Amato of this cycle,” the Democratic strategist said, referring to former Sen. Alfonse D’Amato (R-N.Y.), who was defeated in 1998. “He’s demon No. 1. A lot of the so-called left-leaning groups will be anxious to put up money to knock him out.”

Aside from money, geography is always an important factor in Pennsylvania races, and contributed to Casey’s 2002 defeat in a gubernatorial primary. (Casey has long aspired to the same office his father held from 1987 to 1995, which has led some in the state to quietly question how strong his desire to run for Senate might be.)

Casey was defeated soundly by now-Gov. and former Philadelphia Mayor Ed Rendell in a 2002 Democratic gubernatorial primary. Rendell went on to easily win the governorship, as record numbers of voters from across the political spectrum turned out in the Philadelphia area.

In the primary, Casey won 57 of 67 counties and every media market outside of Philadelphia. But Rendell’s support in the Philadelphia area was insurmountable for Casey, whose family hails from Scranton. Rendell won the race 57 percent to 43 percent.

While there is little doubt that the eventual Democratic Senate nominee will be boosted by Rendell’s presence on the 2006 ballot, Casey’s ability to excite those same voters in the Democratic-rich southeastern region remains the biggest question mark.

“The candidate who runs against Santorum has to have people in the southeast falling over themselves to vote,” said the state Democratic consultant. “And that’s not Casey.”

Meanwhile, Roemer’s entrance into the DNC race sparked an outcry from women’s groups. Kate Michelman, former president of NARAL Pro-Choice America, briefly threatened to enter the race in protest of Roemer. She has since said she is not running.

Roemer has said he’s confident that DNC members will not have a “litmus test” on issues like abortion, and last week he got the backing of two abortion rights supporters, Reps. Ellen Tauscher and Anna Eshoo, both of whom, like Roemer, are Catholic.

“As chair of the DNC, he will not set policy nor will he propose altering the Democratic Party platform on this issue,” Tauscher and Eshoo wrote in their letter endorsing Roemer.

Other candidates vying to succeed outgoing Chairman Terry McAuliffe include former Vermont Gov. and presidential candidate Howard Dean, former Texas Rep. Martin Frost, former Denver Mayor Wellington Webb, New Democratic Network President Simon Rosenberg and party strategist Donnie Fowler.

Kristen Day, executive director of Democrats for Life and a chief of staff to then-Rep. Jim Barcia (D-Mich.), argues that Roemer’s selection as DNC chairman and Casey’s nomination in Pennsylvania would show that the party is inclusive and could help bring disaffected mainstream voters back into the fold.

“You have pro-life Democrats out there supporting Republicans because they just don’t feel comfortable with their own party over the pro-life issue,” Day said.