Sixty-one incumbents, including five legislative leaders, are in contested primaries. That's the most since 1980, when 68 sitting lawmakers faced primary-election opponents.
The incumbents are asking voters to consider their full legislative records -- not just how they voted on the pay raise, which was later repealed. They are also touting their experience in Harrisburg.
The challengers, many of whom are endorsed by a group whose goal is to oust all incumbents, argue that their outsider status makes them better suited for making the Legislature more accountable to the public.
Voters must decide whether they know the challengers and their viewpoints well enough to vote out familiar incumbents who have tried to increase their visibility in recent weeks, either by knocking on doors or through campaign advertising.
"It could well be that a few incumbents will be knocked off, but the odds overwhelmingly favor those with the greatest name recognition and longest relationships with the voters," said Don Kettl, director of the Fels Institute of Government at the University of Pennsylvania.
Voters also will choose Republican and Democratic nominees to compete for 30 open seats resulting from incumbent retirements, the largest number since 1992, when 39 seats were open.
The numbers: In all, 228 legislative seats are up for grabs this year, including all 203 in the House and 25 in the Senate. Of those, 137 -- or three out of five -- are held by incumbents who are unopposed in the primary.
Separately, a special election will be held on the same day to fill a vacancy created by the death of Sen. Robert J. Thompson, R-Chester, whose term expires in 2008.
Three of the most closely watched legislative races involve high-profile leaders who have more than 70 years of collective experience in the Legislature: Senate President Pro Tempore Robert C. Jubelirer, R-Blair; Senate Majority Leader David J. Brightbill, R-Lebanon; and House Minority Whip Mike Veon, D-Beaver.
All three voted in July to enact the law that boosted lawmakers' salaries by 16 percent to 54 percent, and Veon was the only lawmaker who voted against repealing the raises in November. To protect their jobs, each has raised hundreds of thousands of dollars since the beginning of the year. Jubelirer leads the pack with nearly $1.3 million.
Salary boost: The pay raise was passed in the wee hours of July 7 without a public hearing or floor debate. Further angering voters, the law contained a provision that allowed legislators to cash in immediately despite a state constitutional ban on midterm raises.
Jubelirer has two opponents -- Blair County Commissioner John Eichelberger, a longtime political foe, and farmer-publisher C. Arnold McClure. Tire salesman Mike Folmer is hoping to unseat Brightbill, and retired teacher Jay Paisley is challenging Veon.
One lawmaker who withdrew from the primary after his nominating petitions were challenged in court is still hoping to win his party's nomination as a write-in candidate.
Rep. Michael Diven, R-Allegheny, would need 300 write-in votes to secure the nomination, according to the Department of State. Democrat Chelsa Wagner is the only candidate listed on the primary-election ballot in Diven's district.
Watched races: In the House races, which account for the overwhelming majority of contested primaries, Republican and Democratic campaign strategists are monitoring several incumbent challenges in the south-central and western regions of the state, where pay-raise antipathy is believed to be strongest. But they play down the potential impact of the pay raises in those races.
"Who the opponent is means so much more than what the pay-raise issue has ended up meaning in these primaries," said Dan Wiedemer, executive director of the House Democratic Campaign Committee. "The pay-raise issue was probably more potent when it was generic incumbent versus no-name challenger."
Al Bowman, a spokesman for the House Republican Campaign Committee, said property taxes and taxes in general have emerged as more important issues than the pay raise, and challengers aren't likely to spur voter interest without explaining how they would do a better job.
"To come out and vote, (people) need a reason to vote for a candidate, not against a candidate." Bowman said. "A lot of these opponents are not that experienced, they don't really have a record on these issues, and they don't offer any action-oriented agenda."
Other House races considered to be competitive include House Minority Leader H. William DeWeese's contest with Fayette County Treasurer Robert M. Danko, and the GOP primary between Rep. Bob Allen, R-Schuylkill, and Schuylkill County Controller Gary Hornberger.
In Brightbill's campaign travels, constituents bring up the pay raise, but only occasionally, said Erik Arneson, his campaign spokesman.
"A significant majority of the people we talk to realize that it has been repealed, and most people, when you make a mistake and fix it, realize that's the end of the process," Arneson said.
Voter anger: The oust-the-incumbents group PACleanSweep has tried to stoke voter anger over the pay raise and is backing 40 candidates who are challenging incumbents in the primary, although some of the challengers are running against each other in the same districts.
PACleanSweep's interim chairman, John Ryan of Quakertown, said a higher-than-normal voter turnout would help all of the challengers.
"The citizens of Pennsylvania are intelligent enough to make decisions -- the problem is getting them to the polls," Ryan said.
Turnout in primary elections typically ranges between 20 percent and 25 percent statewide.
RoseMarie Swanger, a former Lebanon County commissioner who is running under the PACleanSweep banner, said voters she's encountered on the campaign trail have not forgotten the pay-raise vote.
"They are upset about the pay raise, and they tell me they're waiting to vote on May 16," said Swanger, who is challenging Lebanon County Rep. Pete Zug in the GOP primary. "They also talk about the perks that legislators have given themselves ... things the ordinary person does not get."
Recent voting trends have shown that between the primary and general elections, only a handful of incumbents typically get voted out of office.
The last time a Pennsylvania legislative leader was defeated in any election was 1964, when Republican Senate President Pro Tempore M. Harvey Taylor lost the primary, said Michael Young, a retired public-affairs professor at Penn State-Harrisburg who runs an opinion-research firm.
Young envisions a few possible scenarios, with both sides potentially claiming victory if the result falls somewhere between the extremes of total victory or total defeat for incumbents.
"If no leaders lose, and only a small handful of incumbents lose, then I think the game will be pretty much up," Young said. "They will be explained as local races with local issues, determined by local events."