LONDON (Reuters) – Oil prices fell sharply on Monday on speculation that a U.S. election win for Senator John Kerry could ease the geopolitical friction that has helped fuel this year’s record-breaking rally.

U.S. light crude (CLc1: Quote, Profile, Research) settled down $1.63 to $50.13 after diving as low as $49.30 a barrel, breaking below $50 the first time in nearly a month. U.S. crude peaked a week ago at $55.67 a barrel.

In London, Brent crude (LCOc1: Quote, Profile, Research) lost $1.92 to $47.06 a barrel.

Energy analysts said a win for the challenger Kerry in Tuesday’s U.S. presidential election could mean lower crude prices than if President Bush were reelected. Latest opinion polls can barely separate the two.

“Under a Kerry administration we’d likely have a much more interventionist SPR policy,” said Jamal Qureshi, market analyst at PFC Energy in Washington. “And when you look out a bit further, Bush is more likely to be aggressive in the Middle East, particularly in Iran.”

The Bush administration continues to add crude to the SPR, the national strategic petroleum reserve, despite high prices.

Kerry says he would stop filling the reserve at current prices to keep more crude on the market. That difference is important for a world oil market suffering a shortage of light, sweet crude, which makes up about 40 percent of the SPR.

“A Bush status quo results in somewhat higher oil prices both in the short and the longer term, in my view,” said Tim Evans, senior analyst at IFR Energy Services.

PFC is forecasting an average U.S. crude price of $43 a barrel in 2005 should Kerry win, compared with $48 a barrel in the event Bush triumphed. It sees $52 on average in the first quarter 2005 under Bush compared with $45 under Kerry.

PFC said a Bush win could stoke nervousness about U.S. policies in the oil-producing Middle East, while Kerry is seen as more likely to work through diplomatic channels.

A Kerry victory could also mean more financing for renewable energy sources and trigger a push for tighter mileage standards for gas-guzzling sport utility vehicles.

“Conservation, in my opinion, is the only way to get us out of this hole which we put ourselves in,” said Fadel Gheit, senior energy analyst at Oppenheimer & Co.

Kerry backs a 10-year, $30 billion energy package that includes $10 billion to build cleaner coal-fired power plants and $10 billion to help U.S. auto makers retool to build more fuel-efficient cars.

Traders also are wary of economic data showing signs that higher energy costs are eating into economic performance, curtailing oil demand growth.

A Reuters survey released on Monday showed growth in manufacturing slowed from the euro zone to Japan in October.

The surveys of manufacturers around the world showed a fall in manufacturing for the euro zone, the world’s second largest economic bloc, signaling the slowest growth in 10 months.

“Primarily we suspect this is an oil-price-induced global downturn which is hitting export growth,” said Chris Williamson, chief economist at NTC Research, which compiles the data for Reuters. “Secondly, there has been some evidence of demand cooling in China.”

China’s surprise decision last week to raise interest rates is thought unlikely to have a major impact on fuel demand from the world’s second-biggest user, partly because retail prices remain heavily subsidized.

Also undermining oil on Monday was last week’s restoration in U.S. Gulf of Mexico output from September’s Hurricane Ivan. Production rose nearly 100,000 barrels per day last week to over 80 percent of the normal 1.7 million bpd.

In addition, producer Shell said Monday it would delay engineering work on its 150,000 bpd Gulf of Mexico Mars platform from November until early 2005.

(Additional reporting by Richard Valdmanis in New York)