Today is the official deadline for returning 2010 census forms.

Most Americans understand that a national census is conducted every 10 years, as mandated by the Constitution. Most people also realize that an accurate head count is important and helps ensure fair, population- based distributions of federal funding. But what most people don't realize is that politicians in most states use redistricting tied to the census to alter state legislative boundaries as well as congressional districts to suit their own, partisan interests.

The term gerrymandering dates back to the early 1800s when Gov. Elbridge Gerry of Massachusetts allowed an oddly shaped district to be drawn by state lawmakers. The district's outline was said to resemble a salamander, and at that point gerrymandering entered the political dictionary.

Though redrawing political boundaries might sound benign, it is widely believed to pervert the political process and contribute to extreme partisanship and gridlock.

In civics classes, students are taught that voters choose their elected officials. But in reality, through gerrymandering, incumbent politicians chose their voters. Redistricting is used by the party in power to create a safe district for one party or the other. Republicans and Demo-crats are equally guilty of gerrymandering abuses.

With a gerrymandered district, one party holds a significant registration advantage — and the result of that imbalance is that general elections are foregone conclusions, one party or the other a predictable winner. When general elections are mere formalities, the primary election is all-important. And the candidates with the best chance of winning a primary in a heavily Democratic or Republican district are more likely to move toward the extremes. By moving away from the political middle and appealing to the rabid base — either far right or left — the candidates arouse their base, who tend to be dependable voters, Once elected, they bring that strong partisan bent to Congress or the state Legislature.

Gerrymandering contributes to incumbent re-election rates of 90 percent, politicians for life and attitudes of entitlement and greed. Compromise becomes a dirty word and a prescription for election defeat.

Gerrymandering has been going on for 200 years, but that's no reason for it to be tolerated any longer.

A few states, notably Iowa, have taken redistricting away from politicians and shifted the job to a non-partisan commission.

In Indiana, one lawmaker is pushing a bill requiring that new legislative districts be compact, respecting county and township lines.

In Pennsylvania, there is no need for a new law because Article II, Section 16, of the state constitution says, "Unless absolutely necessary, no county, city, incorporated town, borough, township or ward shall be divided in forming either a senatorial or representative district."

The law could not be more clear, yet it's routinely ignored by politicians in Harrisburg — and elsewhere, where other states have similar provisions.

In eastern Pennsylvania, the 172nd state House District illustrates the absurdity of gerrymandering. In the graphic to the left, the shape of the district in 1992 is shown to be relatively compact. But by 2002, state Rep. John Perzel, R-Philadelphia, decided he did not want to risk election defeat and helped redraw the district lines.

The result of Perzel's efforts to eliminate Democratic-leaning areas and include more Republican voters created the bizarrely shaped district created following the 2000 census.

Much like their 2005 middle-of-the-night pay-raise vote and the greedy pension-grab vote of 2001, state lawmakers involved in gerrymandering illustrate arrogance, entitlement and a total disregard for the law as clearly explained in the state constitution.

There are various efforts around the country to stop the abuses of gerrymandering. Pennsylvanians should join that effort by insisting that lawmakers obey the law and avoid creating gerrymandered districts as a result of 2010 census results. All candidates for state office should be pressed to go on record opposing gerrymandering and vowing to work toward redrawing already-contorted districts with more logical and compact boundaries.

In most state capitals across the country, gerrymandering has gone on unchallenged for years, because both parties do it. Apart from creating jobs-for-life for most incumbents, the twisted boundaries disenfranchise millions of voters by artificially muting their say in elections.

The April 1 census deadline is no April Fools' Day joke. But voters should be reminded on this day that they have been treated like fools by elected leaders in state capitals every 10 years when partisan redistricting has taken place.

It's time for that to stop.