There are several important lawsuits taking place at the state and national levels that could impact the way politicians from both parties handle the explosive issue of redistricting and gerrymandering.

Redistricting or reapportionment is the exercise by which new state legislative and congressional district boundaries are redrawn every 10 years after the federally required U.S. census.

In a nutshell, gerrymandering is intended to establish a political advantage for a party by manipulating district boundaries, sometimes in the most bizarre ways.

In Pennsylvania there is a trial going on this week — Agre v. Wolf — that challenges the way the state’s 18 congressional districts were redrawn following the 2010 census. Republicans wound up in control of 13 of the 18 congressional seats, even though the state’s voter registration numbers favor Democrats.

In the five-county Times News area, one of the four representatives is a Democrat — Matt Cartwright of Scranton, who represents all of Schuylkill County and parts of Carbon, Monroe and Northampton counties. The Republicans are Lou Barletta of Hazleton, who represents parts of Carbon County; Charlie Dent of Allentown, who represents all of Lehigh County and parts of Northampton County, and Tom Marino of Williamsport, who represents parts of Monroe County. Democrats have voter registration leads in four of the five local counties — Carbon (but only by 121), Monroe, Lehigh and Northampton. Republicans lead in Schuylkill.

Republicans have consistently pointed out that there should be no mystery as to why they have a lopsided edge. While Democrats enjoy big voter registration edges in Philadelphia and its suburbs, the Pittsburgh area, the city of Allentown, Centre County (home of Penn State University) and the city of Scranton, the GOP owns much of the rest of the state by wide majorities.

The reapportionment process has always been suspect, especially since it has become so politicized in modern times. The task of redrawing the lines every 10 years falls to a commission made up of the majority and minority leaders of the state Senate and House and a fifth member chosen by the other four. Since the four could not agree on a fifth member the last time around, the Supreme Court appointed Superior Court Judge Emeritus Stephen J. McEwen Jr. to chair the commission. Although he is a lifelong Delaware County Republican, he was described at the time as a “highly respected jurist.’’

The legislative leaders who served on the commission, which is now disbanded, were then-Senate Majority Leader Dominic Pileggi, Senate Minority Leader Jay Costa, House Majority Leader Mike Turzai and House Minority Leader Frank Dermody.

According to the results of an exhaustive investigation by philly.com, lawyers for House Speaker Turzai and Senate President Pro Tempore Joe Scarnati fought to keep a number of the reapportionment reference documents and maps private in preparing for this week’s trial. They also allegedly tried to block revealing the documents in a separate gerrymandering trial that is scheduled to begin next week in Harrisburg.

These documents included data on how voters were leaning politically when the maps were created. According to philly.com, the data show and appear to confirm the belief that Republicans had intentionally drawn the map to favor their party.

These detailed maps of 9,000 voting districts in the state show the races and ethnicities of voters and results from state and national elections from 2004 through 2010.

Of course, when Democrats held the legislative majority, similar accusations were made against them. The Republican organization nationwide decided to make a concerted effort to use their majorities in state legislatures to draw maps favorable to GOP officeholders to ensure “safe” districts. This is done by moving minority voters into already heavily Democratic districts, critics contend.

When the U.S. Supreme Court heard arguments in October on a Wisconsin redistricting/gerrymandering case, members showed a sharp divide. The liberal justices were open to the idea that courts should intervene when lawmakers draw election maps that seem to favor one party over another, while the conservative justices were skeptical about finding a way to determine when legislators had stepped over the line.

This case, along with two others being considered by the high court from North Carolina and Virginia, could have nationwide impact on similar cases, including the ones in Pennsylvania. A court ruling is expected later this term.

By Bruce Frassinelli | tneditor@tnonline.com