For two decades, Republicans in the state's most populous suburban county have been fussin', fightin' and feudin'. And all that brawling has left its mark.

A history of infighting, renewed this week in the bitter political divorce of the party's two top elected officials, has diminished the power of the Montgomery County GOP and has accelerated Democratic gains across the border from Philadelphia.

"We just haven't been able to pull together as a party, and this goes back 15, 20 years," said Ken Davis, the party chairman.

"Over time," he said, "this has been very hurtful to our election success."

When Republican James Matthews cooked up a deal at midweek to share power in Norristown with a Democrat and squeeze out fellow Republican Bruce L. Castor Jr., it was yet another act of self-inflicted blood-letting.

Matthews and Castor, running mates in this year's election for county commissioners, detested each other from the start.

After both won in November, setting up what normally would have been a ruling alliance in county government, no one expected a flawless marriage. But neither did anyone expect an instant annulment.

Matthews' move is not without precedent. In 1991, newly elected Republican Commissioner Mario Mele took a step that was strikingly similar.

It happened in what was yet another chaotic year in county GOP politics, and it also involved personalities.

Republican Paul B. Bartle, longtime chairman of the Board of Commissioners, had grown too big-headed in the view of some Republicans, including Bob Asher, a former state and county party chairman.

Bartle's rise came when there was a leadership vacuum caused by power broker Asher's absence from the political scene in the late 1980s after his conviction on bribery-related charges involving a state contract.

By 1991, Asher was back as a behind-the-scenes force. He helped run candidates against both Bartle and another GOP incumbent, Floriana M. Bloss, in the primary.

The insurgents won. Mele and Jon D. Fox were in. Bartle and Bloss were out.

But after beating the Democrats in the fall, Mele and Fox had a breakup. Mele formed an alliance with Democrat Joe Hoeffel, with whom Matthews made his deal this week.

Looking back on that schism, Bartle, now a lawyer in Norristown, said yesterday: "You get in office over a long period of time, and it's just natural to create some enemies."

Asher, a widely respected member of the Republican National Committee from Pennsylvania, said, "I don't want to talk about the past; I only want to talk about the future." He said he preferred to abide by Ronald Reagan's commandment to speak no evil of another Republican.

Those party wars contributed in 1992 to another Republican disaster. For the first time since 1916, Montgomery County elected a Democrat, Marjorie Margolies-Mezvinsky, to Congress.

Fox won back the seat in 1994. He then lost to Hoeffel in 1998.

As the demographics of Montgomery County have changed, Democrats have chipped away at what for decades had been the most powerful Republican fortress in Pennsylvania.

In November, they won five row offices in the courthouse. They held high hopes of even winning control of the Board of Commissioners, which the party had not done in a century. The hope was based in part on GOP discord left over from a 2004 fight involving Castor.

Frank Bartle (no relation to Paul Bartle) was party chairman then. He had a rift with Asher, a former mentor.

Bartle backed Castor, the district attorney, in a primary for state attorney general. The problem was that the statewide party organization was backing Tom Corbett of Western Pennsylvania, and so was Asher.

The battle, which Corbett won, split the party again at the county level.

Old hands among Republicans say it was one thing for the party to fight in the 1980s and early '90s, when it was still largely unchallenged in local elections.

But now, with Democrats making gains, splits are far more dangerous, they say.

Though county voters have continued to leave Republicans in control in Norristown, they have voted for Democrats for president in every election since 1992.

In 1987, Democrat Bob Casey got clocked in Montgomery County while running for governor. Last year, his eldest son, Bob Casey Jr., easily won the county in his successful run for the U.S. Senate.

Republican Tom Ellis, a departing commissioner who plans to run for state treasurer next year, said there was no doubt that infighting had damaged the party.

"It has hurt us in elections, and it has hurt us in stature," he said.

There is another problem undercutting Republican power in Montgomery County. The national Republican Party, with a more conservative tilt than in decades past, has left many former GOP voters feeling "the party had left them," Ellis said.

All of which makes unity more important.

Policy issues aren't what have divided the county GOP.

"The Montgomery County wars have been personality- and people-based, more than policy-based," said Mark Holman, a Western Pennsylvanian who was chief of staff for former Republican Gov. Tom Ridge.

The fights have often left state GOP leaders throwing up their hands in frustration.

In 2001, when boundary lines for congressional districts were redrawn to reflect population shifts, Republicans in Harrisburg controlled the process.

Davis said state GOP leaders penalized the county by carving up its main congressional district, most of which was in Montgomery County, among several counties.

"I think it was Harrisburg's response to the disunity here," he said.

Paul Bartle, long out of elective politics, said the feuding made him think of the Hundred Years War in the late Middle Ages.

"Families can fight for a long time until they get it together," he said. "There has not been the willpower to just say, 'Stop!' "

Contact staff writer Tom Infield at 610-313-8205 or tinfield@phillynews.com.