LONDON — IN the United States, power-seekers are trying to conquer the political right because -- as House Speaker Newt Gingrich and other Republicans well know -- that is where public sentiment is moving.
But on this side of the Atlantic, party leaders, conservative or otherwise, are scrambling to avoid extremes and ''seize the middle ground,'' for they realize that is where votes beckon.
Stakes are high -- the opposition Labour Party seeks to unseat Conservatives from 15 years of rule in general elections, which are due in two years. The party that woos the middle class wins.
''Prime Minister John Major knows that if Labour succeeds in dominating the political center, it will be because the Conservatives after 15 years in power have surrendered it,'' says a Labour strategist.
Both parties will have to sacrifice some of their most cherished ideals to earn broad-based support. Labour's new leader, Tony Blair, has shown that he wants to ditch the famed Clause 4 of his party's constitution -- a commitment to nationalized industry that has lasted 50 years.
Another Labour adviser puts the strategy in terms of social class.
''To win the middle ground, we have to capture the hearts and minds of a large swath of the middle classes who have kept the Conservatives continuously in power for 15 years,'' he said. ''We can't do that by sticking to policies that frighten voters off.''
The adviser noted that in leaning to the center, Mr. Blair is reflecting a European trend.
He pointed to France, where this year's presidential election ''seems likely to be won by a candidate of the conservative center,'' and Spain, where socialist Prime Minister Felipe Gonzalez ''is struggling to retain the middle class support that has kept him in office since 1982.''
Conservatives are facing their own tough decisions -- over the party's stand on Britain's role in the European Union. On March 1 in the House of Commons, Mr. Major was to defend the government's policies by trying to steer between right-wingers, eager to keep the EU from dominating Britain, and pro-Europeans, who say the country must contribute to an ever-deepening union.
The prime minister is counting on opinion polls, which show between 60 and 70 percent of voters would probably not support actual withdrawal from the union.
Jeremy Hanley, the Conservative party chairman, says Major's approach is ''to unite the party around policies on Europe which our traditional heartland of support will be happy with.''
Blair insisted on Feb. 25, however, that ''the Conservatives are hopelessly divided on Europe.''
One of his advisers said Labour policies are ''at least consistent, and likely to benefit middle-income earners who like what the EU has to say about job protection, a minimum wage, and better working conditions.''
BRITISH politicians have been quick to spot the significance of the growing middle class.
Some 32 percent of Britain's labor force is still blue-collar workers, but Anthony Giddens, professor of sociology at Cambridge University, says the proportion is likely to diminish.
Mr. Giddens says this could suggest that Labour will lose its ''natural constituency,'' while the Conservatives gain ground.
But he adds that the Thatcherite policies of the 1980s have made the English middle classes feel more insecure. Blair is trying to ''renew the security which aggressive free-market policies have helped dissolve.''
In a MORI/Times poll published Feb. 24, fewer than 1 in 10 Britons said they were happy with the way Major's government is running the country.
The poll also showed that professional middle-class voters feel gloomy about the economy, with only 21 percent believing it will improve, compared with 36 percent a month earlier.
The poll bodes ill for Liberal Democrats, traditionally a centrist party. Their support is static at about 14 percent -- evidence, a Labour spokesman said, that ''we now speak for middle Britain.''