Tuesday, February 23, 2010

The art of the Gerrymander

Gerrymandering is not an Irish invention. In fact the term comes from the US where a Governor Gerry of Massachusetts redistricted the state in 1812 to include an extremely long and narrow constituency shaped somewhat like a salamander. The merger of the governor's name and the animal shape gave us the word we now all know and love.

With single member constituencies in a two party system (UK or US) the normal form of gerrymandering is to redraw the borders so that each incumbent is a relatively safe seat. In a region with 50/50 support for each side and two seats to fill, it is relatively easy to redraw borders so that each of the parties win their seat with a 55/45 or stronger margin. The Redistricting Game is an excellent website that explains with many examples the entire process. There are many interactive demos and games that allow you to redraw the borders to suit any political end.

Despite not inventing the term, Ireland has not been a late arrival at the gerrymander. Until the introduction of the independent Constituency Commission about 20 years ago, the lines on the map were completely under the control of the Minister for the Environment. DeValera carved up the country with plenty of three seat constituencies to fend of the advances of Clann na Poblachta after the Emergency.

In the 1970's Labour's Jim Tully tried to retain power for the FG/Lab coalition by creating plenty of three seat constituencies with the view that each of FF, FG and Lab would win a seat each. The plan disastrously backfired with FF winning two out of three in many of the constituencies in the 1977 election leading to the giveaway budgets of the Lynch government. The failure has lead to the term Tullymander where the redrawing of boundaries spectacularly fail to achieve the desired result.

In the PR-STV system the gerrymander tends to be based on the number of seats for a given district rather than making non-compact constituencies. The smaller the number the easier it is for the bigger party or name in an area to win. Larger areas, while somewhat favouring the smaller parties are also more representative of the entire area. A candidate that consistently polls 12% across an area will get elected in a 6 seater but will have no hope if the area is divided into two 3 seaters.

Taking a more simple example, imagine an area with two seats, split into two areas A and B. FF polls well in area A but very poorly in B, FG the other way round and Labour consistently across both districts. Assume the 2nd preferences for each ballot are evenly split between the other two candidates.

Area A
Area B
45% 20% 35% 20% 45% 35%
In this case both FF and FG would be best served by having two separate single seat constituencies as the transfers would elect one representative from each party. In a single two seat constituency, Labour would be elected on the first count with FF and FG slugging it out for random votes in the Labour surplus.

The power to set terms of reference for the Constituency Commission can still have a great influence on the outcome of any boundary review. In the interests of electing the candidates most representative of the views of the electorate it is vital that small, gerrymandered constituencies are removed and large multi-seat constituencies are created.

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