Washington ? When Barack Obama decided last week to throw off the constraints on campaign spending that go with the acceptance of public financing, he was rightly criticized for rigging the system in his own favor.

That was a predictable response. For the better part of four decades, the press and public interest groups have focused on campaign spending as the most serious distorting force in our elections.

Meantime, they have paid much less attention to what may well be a larger problem – the way that district lines are drawn to create safe havens for one party or the other, in effect denying voters any choice of representation.

It is not a new problem. The original gerrymander was a creation of 18th-century Massachusetts, and politicians have been using ever more sophisticated tools to rig the game ever since. With computer technology, their ability to design districts that meet the legal requirement for equal population, while guaranteeing their fellow partisans easy passage into office, has never been greater.

In 2002 and 2006, the most recent off-year elections, about nine out of 10 congressional districts were won by more than 10 percentage points – a clear sign that the game had been rigged in advance, when the lines were drawn in the state legislatures. In the first of those years, only eight incumbents lost; in the second, only 21.

As a number of scholars have pointed out, the scarcity of real competition in nearly all districts has many consequences – all bad. It makes legislators less responsive to public opinion, since they are in effect safe from challenge in November. It shifts the competition from the general election to the primary, where candidates of more extreme views can hope to attract support from passionately ideological voters and exploit the low turnouts typical of those primaries.

Gerrymandered, one-party districts tend to send highly partisan representatives to the House or the legislature, contributing to the gridlock in government that is so distasteful to voters.

These are familiar complaints in academic and journalistic circles. And this week, another count was added to the indictment, with a report from the Democratic Leadership Conference titled “Gerrymandering the Vote.”

It makes the point that these rigged districts have the effect of suppressing the vote.

The numbers are startling. In both 2002 and 2006, voter turnout in districts where the winner received at least 80 percent of the votes struggled to reach 125,000. Turnout in the districts where the margin was 20 percent or less exceeded 200,000.

If there were some other device that was reducing voter turnout by almost 40 percent, you can be sure it would be the chief target for reformers. The ballot anomalies and the “voter suppression” tactics that marked the Florida election of 2000 affected far fewer people than that.

The study compiled by the DLC’s Marc Dunkelman found big variations among the states in the competitiveness of their House districts. The average margin in Massachusetts in 2006 was almost 75 percent. Next door in New Hampshire, it was under 5 percent.

Dunkelman calculated the potential turnout increase for individual states, if their district lines were redrawn to emphasize competitiveness. The gains ranged as high as 59 percent for Louisiana and 49 percent for New York. Other states which could see much higher public participation with redrawn districts include West Virginia, Virginia, California, North Carolina, Alabama, New Jersey, Mississippi, Georgia, Hawaii and New Mexico.

Dunkelman estimates that competitive districts might attract 3 million more voters in California and almost 2 million more in New York. Overall, 11 million more Americans might show up at the polls, helping mitigate our chronically low voting participation rates.

How to change the lines? Two states – Iowa and Washington – have instituted nonpartisan or bipartisan redistricting systems, and have been rewarded with much more competitive House races. So it can be done.

But the politicians are unlikely to do it on their own. Only if the voters demand reform is there a chance it will come.