LONDON — Britain's messy, unresolved election may have created the conditions for fundamental change of a voting system that has inspired democracies from the United States to India.
The first-place Conservatives are negotiating with the Liberal Democrats in the hope of getting a majority in parliament. That gives the third-place party hope they now have enough leverage to introduce a change that would alter the face of British politics – potentially sweeping away the two-party system in favor of a European model in which coalitions are the order of the day.
Their demand looms as a huge sticking point in negotiations with the Conservatives, who have just moved close to power thanks to a system that rewards the party that claims the most first-place finishes in individual districts, as in U.S. Congressional elections.
As observers speculate that the Lib Dems may be ready to compromise their decades-long push for reform to get a shot at government, about 1,000 demonstrators gathered at Westminster, Britain's seat of power, on Saturday to demand that the Liberal Democrats hold firm.
"The fact that you are here, out on the streets in central London now because you care so much about political reform is absolutely wonderful," Lib Dem leader Nick Clegg told the noisy crowd, which, like him, backs proportional representation, which would base the number of a party's representatives in Parliament on percentage of votes cast for them.
It's obvious why the Liberal Democrats yearns for change: In this election, 23 percent of the vote gained them 9 percent of the seats in the House of Commons.
The perceived unfairness of that system was evident at Saturday's protest, where many carried placards reading: "Fair Votes Now!"
The Conservatives are unlikely to be very interested in electoral reform that helped them gain more seats than their Labour rivals for the first time in 13 years.
"We know that by and large members of parliament tend to support the system that gave them power," Ken Ritchie, leader of the Electoral Reform Society, said Saturday.
Ritchie backs the "single transferrable vote" method used in Ireland: Each district elects three or more members to parliament, and voters mark their ballots in order of preference. Through a complex series of counts, winners emerge.
Germany has a combination of winner-take-all districts and proportional representation. Israel has an extreme version of proportional representation in which 1.5 percent of the vote can win a seat in the Knesset.
Proponents of Britain's existing system say it tends to produce strong one-party governments able to deliver their campaign pledges. Advocates of proportional representation prefer coalition governments which draw in a wider spectrum of opinion, even if individual party promises fall by the wayside.
Britain uses forms of proportional representation for European Parliament elections and local council elections in Scotland, for example. Thomas Hare, a 19th century Englishman, was a leading proponent of proportional representation, but his ideas were first adopted in Tasmania in 1897.
Bill Jones, professor of politics at Liverpool Hope University, said Liberals have been "campaigning for 90 years to change the voting system, and now there's a possibility."
"There is this feeling: 'Here's this one chance. When will it come again?'"
In 1974 the Liberal Party, as it then was, offered to join a coalition with the Conservatives after an inconclusive election – if proportional representation was part of the deal. Tory leader Edward Heath refused, and stood aside to let the Labour Party form a short-lived minority government.
Since then, successive elections have bestowed House of Commons majorities on parties which won less than half the vote. Margaret Thatcher won a landslide in 1983 with 42.4 percent; Tony Blair did the same in 1997 with 43.6 percent.
Before 1997, Blair flirted with proportional representation and negotiated with Paddy Ashdown, then the leader of the Liberal Democrats.
Ashdown has said there was strong opposition within the Labour party, not least from Gordon Brown, now the prime minister, and Labour lost interest in proportional representation.
Brown, however, discovered an interest in proportional representation as the latest election loomed. His government proposed legislation to hold a referendum on the voting system, but that came to nothing.
Hoping to cling to power, Brown made a new pitch to the Liberal Democrats on Friday. "A fairer voting system is essential and I believe that you, the British people should be able to decide in a referendum what the system should be," Brown said.
Lord Norman Tebbit, a Conservative luminary from the Thatcher era, grumbled on Saturday that Clegg was "strutting around like a king maker having been rejected by 77 percent of the British electorate".
"By his own terms of PR, he should be put back in a locked cupboard and told to go away while the big boys sort it out," Tebbit told Sky News.