Top Pennsylvania state legislators think they've figured out why compromise has become more difficult and little seems to get done in a polarized Harrisburg: closed primaries.

House and Senate leaders are calling for changing state election law to allow for "open" primaries, in which voters unaffiliated with the two major parties, colloquially called independents, could vote to choose the nominees of either party — on the principle that involving less-partisan voters would have a moderating influence.

Under the current "closed" system that limits voting to registered party members, in low-turnout primaries party nominees can be chosen by a small percentage of zealous voters, they argue.

"The extremes of the parties have taken over the primary process," Senate President Pro Tempore Joe Scarnati (R., Jefferson) told reporters after the May 15 state primaries. He cited the upset of a Republican state senator in western Pennsylvania by a conservative insurgent and the defeat of two veteran Democratic state representatives at the hands of candidates endorsed by Democratic Socialists of America to buttress his argument. He said he was introducing legislation to open the primaries.

Although it seems to make intuitive sense, academic research and political scientists suggest that an open primary system would not bleach the elections of  polarization and extremism; in fact, it might do the opposite.

"We can rule out the possibility that it's closed primaries that are explaining a vast majority of polarization," said Marc Meredith, a political science professor at the University of Pennsylvania. With open primaries, he said, "at best it's going to make a small dent in a mountain of polarization."

The problem: Most unaffiliated voters have strong partisan or ideological leanings masked by their independent status.

"We find that the openness of a primary election has little, if any, effect on the extremism of the politicians it produces," a team of academic researchers wrote in one study. In fact, it said, "most of the effects we have found tend to be the opposite of those that are typically expected: The more open the primary system, the more liberal the Democrat and the more conservative the Republican."

What political science says about independent voters and primary elections

About 750,000, or 8.8 percent, of Pennsylvania's 8.46 million voters are registered as unaffiliated. Most — 86 percent — are registered as Democrats or Republicans.

"Some areas had 15 percent turnout," said Rep. Dave Reed (R., Indiana) the leader of the House Republicans, who also is introducing legislation that includes opening the primaries. "That doesn't seem like it's representative of the entire populace and giving the most mainstream choices headed into the fall election cycle." He said that would change under an open system.

"All of a sudden, if you get more people coming out to a primary," he said, "the candidates have to be more considerate of everybody's views, not just the 8 percent that in some areas can be fairly extreme."

But Reed is operating under a common misconception that "makes a lot of assumptions about independents," said Robin Kolodny, the chair of the political science department at Temple University. Among the assumptions: "That they're just as engaged, they're just as interested, that they would actually want to participate in a party's primary. Because, of course, they chose to say they're independent."

Although voters choose not to associate with a party for varied reasons, and the parties are increasingly unpopular, voters are still largely partisan and tend to vote strictly within one party. Those moderate, independent voters? An already-small group. Say goodbye to the swing voter.

Take Erica Bates, 46, a teacher who lives in East Mount Airy who registered as an independent last year because she doesn't fully agree with either party. "I'd like to be able to have choice which way I'm going to go," she said.

Bates, a self-described "super voter" who reads through voter guides for local elections, registered as a Democrat for years and has campaigned for Democrats. If she were allowed to participate in primaries as an independent, she'd most likely take a Democratic ballot. Yet she doesn't have a choice; she said she may re-register as a Democrat again to be able to vote in primaries, the election counts in most parts of the blue city.

In Lansdale, Gail Moxey, 68, is today registered as an independent, abandoning the GOP after President Trump's election. But Moxey is a "dyed-in-the-wool conservative Republican," she said — not some moderate stuck between the two parties.

It's a common misconception, Kolodny said: "When you hear independent, everyone immediately thinks moderate instead of fringe."

Lawmakers aren't wrong that polarization is increasingand hostility for the opposing party is entrenched — but the problem evidently is unrelated to closed primaries. The researchers say that people showing up to vote in primary elections tend to be similar to other party members, so it's not that extreme voters are showing up to the polls and hijacking the election.

What open primaries could do

The best argument for open primary elections isn't polarization, Meredith said — it's that some places are so dominated by one party that the primary election is more important than the general election. Places like, well, Philly.

"By and large, the general is the primary election in the sense that who wins the primary election in Philadelphia is going to decide who holds office," he said. "So I think there's definitely a good case to be made that you might want to open up the process, especially at the local level. Because there are probably lots of Republicans in Philadelphia who have opinions about something like who should be mayor and essentially don't have a voice in the process right now."

Under the closed system, those voters would have to switch party registrations back and forth, becoming Democrats for local primary elections and Republicans for presidential ones.

Reed, the House GOP leader, said that giving all voters a voice in those local primaries is one his main concerns: "We are excluding an entire segment of our population, almost 750,000 people in the state, from deciding who their local elected officials are."

What the politicians say

Leaders from both parties expressed support for open primaries, although for differing reasons, and said they are hoping this is just the beginning of a larger discussion about structural reforms to Pennsylvania's election system.

"People should have the opportunity, independents and others, because they need to participate in the process," said Sen. Jay Costa (D., Allegheny), the head of the Senate Democrats. "I'm not looking to do it for the same reasons that Sen. Scarnati's trying to do it. I think for our democracy to work right, the more people need to participate in the process."

Senate Majority Leader Sen. Jake Corman (R., Centre) said he has long been opposed to open primaries — "I believe that you belong to a party and nominate a person from that party to represent you in the fall" — but now is open to the proposal.

"I'm not sure I'd say I'm opposed anymore," he said. "I'm more neutral, more willing to listen, to research a little further."

As a leader, Corman said, his job is to get votes. That historically has meant seeking compromise and working with the other side. Corman said he's concerned that the state legislature is becoming less and less willing to compromise.

Rep. Frank Dermody, head of the House Democrats, said he was "happy to take a look at" proposals to open primaries but would wait to see that legislation before taking a position.

"You've got to read it first, but independent voting in a primary may make some sense," he said.

Gov. Wolf's office said he generally supports the idea, too.

"This is a conversation that's ripe right now," Costa said. "I think the issue certainly has been raised, and I think now is the time to do it."