Using uncertainty to ensure democracy: drawing a responsive electoral system with competitive seats

US redistricting has changed its focus from remedying partisan bias to increasing responsiveness, partly because measurement of bias is inherently difficult and partly because entrenched incumbents have reduced voters' ability to hold their government to account. An increasing number of states now require their redistribution commissions to draw competitive seats where they can. Australia's electoral boundaries are drawn by independent commissions in a process that prevents the commissions from considering the political effect of the lines they draw, except in South Australia where the commission is required to consider precisely those effects in order to remedy partisan bias. That process seems likely to fail whenever it is most needed because it is too hard to predict how marginal seats will swing with any given statewide swing. Perhaps what the commission could do is address bias in the safe seats and draw a few more marginal seats, using uncertainty to ensure that voters can hold their government to account.