When former U.S. Rep. Patrick Murphy, a Democrat, recently told me that he was running for state attorney general, I asked him what made him think he could break the GOP stranglehold on that office.

"The bottom line is that Pennsylvanians are looking for an attorney general who will fight for them, someone who will protect them from crime wherever it might be - on the street, from big special interests, or in Harrisburg. I've dedicated my entire life to protecting American families, and I will be that attorney general," Murphy told me.

So far, no Republicans have announced plans to run for attorney general next year, but if Murphy or any other Democrat wins the office, it will be historic. While plenty of Democrats have been elected statewide since 1980, the year Pennsylvania began electing its attorney general, none has won the top law enforcement position.

Here's a quick review of the history:

In 1980, LeRoy S. Zimmerman rode Ronald Reagan's coattails to a close victory (2.8 percentage points) over Michael O'Pake. Four years later, Zimmerman eked out the smallest margin of victory for an attorney general's race when he defeated Allen Ertel by 0.6 percentage points.

Then Ernie Preate Jr. defeated Edward Mezvinsky in 1988 by 3.3 percentage points. In 1992, Preate beat Joe Kohn by 2.7 percentage points. Four years later, I recall, I went to bed thinking Kohn had defeated GOP nominee Mike Fisher, but in the light of Wednesday morning, Fisher had built an advantage of 1.6 percentage points.

With George W. Bush and Al Gore at the top of their tickets in 2000, Fisher was reelected, defeating James J. Eisenhower by 10.9 percentage points, the largest margin recorded for an attorney general's race. Four years later, Eisenhower came much closer, but not close enough. Tom Corbett won by just 1.8 percentage points. In 2008, Corbett defeated John M. Morganelli by 6.7 percentage points.

Adding to the mystery of this GOP dominance is the state's Democratic voter registration and the fact that elections for attorney general have taken place in presidential years in which several Democrats at the top of the ticket have carried the state.

"As they say, it's complicated," began Terry Madonna, the longtime pollster and director of the Center for Politics and Public Affairs at Franklin and Marshall College, when I sought his explanation. He noted that Republicans had generally run "super D.A.s, who had strong prosecutorial records to run on," such as Zimmerman (a former Dauphin County district attorney); Preate (a former Lackawanna County district attorney), and Corbett (a former U.S. attorney who was appointed attorney general in 1995). By contrast, Madonna noted, the Democrats "have tended to run lawyers mostly known for their political careers," such as O'Pake, a state senator, and Mezvinsky, who had served in the U.S. House.

Eisenhower was the exception. The former assistant U.S. attorney and Justice Department lawyer reiterated that assessment: "First and foremost, the Republicans have been very successful in convincing voters that the office is a 'big D.A. office' and have nominated candidates who stress traditional law enforcement issues like drug and gun prosecutions."

Madonna also surmised that the power of incumbency in statewide row-office elections was a factor for the Republicans. "They can use their office, prosecutions, and other high-profile activities to get themselves reelected," he told me.

Democratic challengers haven't had high-profile last names like Rendell or Casey, nor have they been particularly outstanding fund-raisers, Madonna added.

Eisenhower added that the GOP had enjoyed a fund-raising edge by convincing its campaign contributors that the race for attorney general mattered to them. "Because we have never held the office, many Democratic givers don't understand the office and simply don't care who the attorney general is," he said.

There is also the likelihood that voters in both parties tend to associate law enforcement with the GOP. Madonna speculated: "The Republicans are more trusted by the voters on issues involving crime. Maybe the Republican network of police, sheriffs, and correctional organizations has been a bigger help to GOP candidates in elections where the voters have only a little sense of the candidates."

That theory has perhaps no greater advocate than Zimmerman, who set Pennsylvania Republicans on their trajectory of success.

When I tracked him down and asked him why Democrats had not been able to break through in eight chances, Zimmerman recalled campaigning as an experienced lawyer and prosecutor - a candidate who could fulfill Pennsylvanians' desire for an attorney general who would enforce laws, not mold them.

"Voters have shown their strong and enduring preference for the Republican focus on enforcement," he said. "I believe that is why I was elected. And I believe that is one important reason why all my successors have been from my Republican side of the aisle."

We'll soon find out if Zimmerman's strategy can stand the test of 32 years' time.

Contact Michael Smerconish via www.smerconish.com. Read his columns at www.philly.com/smerconish.