While we're all celebrating Minnesota's good luck in not losing a congressional seat, let us also be aware that an even greater misfortune is likely to occur. Our state, like many others, is likely to engage in the most extreme form of voter suppression.

This voter suppression consists of making each congressional district winnable for only one political party. District A is made up of 70% Democratic voters while District B, right next door, is 70% Republican. So a third of the voters in each district can never elect someone of their own party to Congress. Technically they can vote, but they know that their vote will not count.

Both parties love this. Particularly the incumbent office holders and the increasingly narrow factions that run the parties in most House districts. They're the ones who make this happen.

Every 10 years there's a census, constitutionally required, and following that census new district lines must be drawn so that each district has roughly the same number of voters. It's starting to happen this year.

But the real goal of those who draw the new lines is to make the incumbent impossible to beat. This is easy to do when both sides agree. And they do. Incumbent A feels that sharing a party label with merely 60% of the voters isn't safe enough — 70% would be so much more comfortable. Incumbent B next door, though of the other party, feels exactly the same way.

But say District A has grown in the decade between the censuses. District B has shrunk. The areas of District A inhabited heavily by the minority party will be shifted to District B, where they become part of an increased majority. You scratch my back, I'll scratch yours.

Since the reforms of the British House of Lords, America has become the only major nation whose lawmakers in one house in effect serve for life. (In Minnesota, some districts have recently switched the party of the incumbent, but those exceptions occurred because much time had passed since the original gerrymander and a uniquely polarized election caused some voters, atypically, to change parties. The new incumbents will benefit from a new stacked deck.)

This is more than absurd — it's dangerous. The new norm of single-party districts is a major cause of the polarization of our politics today. It explains gridlock. Because while few incumbents can lose a general election, most are now more vulnerable in their parties' primaries. The lack of a real contest in November has atrophied public involvement in that election. So the local party structure has been supplanted by few but fervent activists who can push extreme agendas.

And woe to the incumbent who fails to support the increasingly narrow party line. The party cannot lose in the fall, but the incumbent can be replaced in the primary by someone less independent. That's why so many votes in the House are virtually unanimous within each party, and compromise has become a dirty word.

Of all the forms of gerrymander, single-party districts are the most corrosive of our democracy.

The cure for this is obvious: make most districts competitive. Draw lines so that each party is pretty close in numbers within each district and the election, therefore, up for grabs.

But who draws the lines? That is of course the real question. At present, legislatures have that power, but the task of redistricting can no longer be left to incumbents and their factions. And letting the job be done by jurists may not bring much change. If judges were not politically aligned they'd still be practicing law.

There needs to be not only an impartial panel created to redraw district lines, but laws in each state mandating that districts be as politically competitive as possible. Iowa has such a law, and it works.

Perhaps the president will be a leader in urging other states to follow this example. It's hard to imagine a single step that would more fundamentally heal our divisions.

David Lebedoff is a Minneapolis attorney and author.