A lawsuit challenging the constitutionality of Pennsylvania's system of funding public schools is now able to move forward to trial.

Commonwealth Court Judge Robert Simpson on Tuesday issued a ruling, denying the last of the preliminary objections made by legislative leaders that claimed the implementation of a school funding formula in 2016, two years after the lawsuit was filed, rendered the case moot.

In his ruling, Simpson stated at this juncture, "there are sufficient legal and factual issues that remain in dispute, such that this court cannot find petitioners' constitutional claims moot."

No trial date has been scheduled.

Bringing the case against state government officials are six families and six school districts, along with some statewide associations. In their lawsuit, they allege the Legislature is not living up to its constitutional responsibility of providing a "thorough and efficient" education system, resulting in underfunding and gross disparities in funding allocations that penalize students in poorer school districts.

In court filings, they argued that the disparity between the wealthiest and poorest school districts has widened by $720 per child, from $3,058 to $3,778 since the new funding formula was put in place.

That is because that new formula applies only to the new dollars invested in basic education since the formula's adoption. The House Democratic Caucus figures the formula applies to just 8.8 percent - or $539 million - of the $6 billion put into basic education funding in the 2018-19 budget.

"We are pleased that the court has denied respondents' baseless attempt to dismiss our lawsuit," said Maura McInerney, legal director for the Philadelphia-based Education Law Center. "As the court recognized, our challenge to the inadequacy and inequity of Pennsylvania's broken school funding system will persist. We look forward to presenting our case at trial."

The families, school districts and statewide associations are asking the court to direct the General Assembly to adopt a fair and adequate funding system and fund it, which could result in a need for increasing the funding for basic education by several billion dollars.

Neal Lesher, a policy director to House Speaker Mike Turzai, R-Allegheny County, said the court ruling on the motion wasn't totally unexpected. Nevertheless, he pointed out that the Legislature has increased overall funding for schools by over $2 billion since 2015, when the new funding formula became law.

"This year, funding is at a historic high of $12.3 billion," Lesher said. "New funding is being distributed through a revised funding formula that was enacted by the legislature in 2015. That formula ensures wealthier districts get less state money than those in need. Crafting a budget, including education funding, is constitutionally a legislative matter that we take very seriously. We continue to believe that this matter does not belong in the courts."

An attempt to get a comment from the chief counsel to Senate President Pro Tempore Joe Scarnati, R-Jefferson County, late Tuesday afternoon was unsuccessful.

Philadelphia-based Public Interest Law Center staff attorney Dan Urevick-Ackelsberg said the funding system as it exists today deprives students of the resources they need.

"We are talking about basics: not enough teachers, out-of-date books, and buildings that crumble around the children inside of them. That was the reality when we filed the case, and it continues today," he said.

Gov. Tom Wolf is among the respondents named in the case; however, he opposed the mootness challenge and urged the court to allow the case to move to trial swiftly.

This is the second time the case has rested in the hands of the Commonwealth Court. The first time, that court threw out the case, saying jurisdiction over school funding is a legislative matter. The petitioners appealed that ruling to the state Supreme Court, which in a divided decision last fall, ruled there are judicially manageable standards for court to review school funding issues. It remanded the case back to Commonwealth Court for a full trial.