Pennsylvania Sen. Arlen Specter (R) eked out a narrow primary victory over Rep. Pat Toomey (R) Tuesday, bringing closure to the all-out-knock-down fight dubbed the ultimate battle for the soul of the Republican Party.

With 99 percent of precincts reporting, Specter edged out Toomey, 51 percent to 49 percent. Voter turnout across the state was extremely light, despite national focus on the race.

Specter’s win sets up a November showdown with Rep. Joe Hoeffel, who was unopposed for the Democratic nomination Tuesday.

Specter benefited heavily from the support of the Republican establishment, including President Bush and Sen. Rick Santorum, his more conservative home state colleague.

He was aided by a last-minute visit to the state by Bush, and a late flurry of ads and telephone messages featuring the president’s request to re-elect the Senator.

Bush’s visit also helped to bolster Specter’s argument that he was best positioned to help the president win the battleground state in November.

“Now is the time, now that we’ve settled our family disagreement in the Republican Party, to unite for victory in November for the president,” the 74-year-old Specter told a cheering crowd of supporters shortly before 1 a.m. Wednesday.

As Toomey and his conservative supporters sought to paint Specter as a liberal wasteful spender, Specter was relentless in touting his seniority and the federal dollars he had helped spread across the state in the last 24 years.

Toomey, 42, was aided by the support of movement conservatives and organizations such as the Club for Growth, which poured more than $2 million into the effort to defeat Specter.

Toomey, who conceded the race around 12:45 a.m., said he was proud “we advanced the cause.” He offered his unequivocal support to Specter, saying, “our differences are not nearly as great as those we have with the Democrats.”

“We had a lot of ideas about the principles and values of the Republican Party,” Toomey said in his concession speech. “These ideas are at the heart of the Republican Party.”

The Lehigh Valley Congressman had confidently predicted last week that he would win the race with 51.7 percent of the vote, as polls showed Specter’s lead had narrowed to just 5 percentage points.

Many Republicans feared a Toomey win would jeopardize the party’s ability to hold the seat in November, while Democrats did little to hide their desire to face the three-term Congressman instead of the incumbent seeking an unprecedented fifth term.

National Republican Senatorial Committee Chairman George Allen (Va.) called Specter’s victory “a great win for Senate Republicans all across the country.”

“Senate Democrats will be hard pressed to defeat Arlen Specter this fall,” Allen said in a statement.

Now that he is officially the Democratic nominee, Hoeffel is embarking on a 17-county tour of the state today.

Democrats immediately sought to paint the battle-tested Specter as damaged goods.

“Tonight’s results, where a four-term incumbent came within a whisker of being turned out of office by his own party, proves that Arlen Specter is vulnerable and the people of Pennsylvania are ready for a change,” said Democratic Senatorial Campaign Committee spokesman Brad Woodhouse. “Specter’s hard turn to the extreme right in the primary will all come back to haunt him in the general election. If Senator Specter thinks he got a fight from Pat Toomey, he ain’t seen anything yet.”

Allen, meanwhile, issued a plea for party unity following the divisive primary.

“It is incumbent upon us as Republicans to come together and emerge from our intra-squad scrimmage as a united team focused on victory in the fall,” he said.

In other Keystone State primary results, state Sen. Allyson Schwartz (D) and wealthy ophthalmologist Melissa Brown (R) will face off in the 13th district race to succeed Hoeffel.

Schwartz, who was backed heavily by EMILY’s List, squeezed by Joe Torsella, the former president of the National Constitution Center, 52 percent to 48 percent. The two candidates spent a combined $3 million in the race.

Brown, in her fourth bid for the 13th district seat, edged out two opponents for the GOP nod, garnering 39 percent.

The stage is now set for an expensive showdown in the swing district encompassing parts of Northeast Philadelphia and Montgomery County.

Meanwhile, in the 15th district race to replace Toomey, state Sen. Charlie Dent (R) and real estate developer Joe Driscoll (D) will square off in November, as expected.

In the six-way, hard-to-predict nomination fight in the 17th district, attorney Scott Paterno — son of Penn State football coach Joe Paterno — edged out teacher Ron Hostetler, a one-time standout on Joe Paterno’s team, for the GOP nomination. Scott Paterno, 31, will face Rep. Tim Holden (D) in the fall.

The Democratic Congressional Campaign Committee wasted little time before firing its first shot at Paterno Wednesday morning, issuing a statement highlighting controversial newspaper columns he wrote in college.

But the biggest surprise in Tuesday’s balloting was in the 9th district primary battle between Rep. Bill Shuster (R) and wealthy political newcomer Michael DelGrosso (R).

Returns showed DelGrosso holding a slim lead for most of the night and it wasn’t until well after midnight that Shuster was declared the winner. With 98 percent reporting, Shuster led 51 percent to 49 percent.

DelGrosso, a 34-year-old Naval Academy graduate, waged a largely self-funded grassroots campaign, knocking on some 10,000 doors over 10 months. His family operates a local amusement park and a food company that mass produces cans of tomato sauce.

Shuster was elected to replace his father, former Rep. Bud Shuster (R-Pa.), in a 2001 special election.