But Democrats and Republicans are deeply split about how to respond. The deadlock in Washington was apparent last month when the Senate failed to pass a bill to double energy assistance to low-income households because Republicans insisted on including measures to allow for more offshore drilling.

Image People are going to have a tough time, said David Moody of Flynns Oil, a small fuel oil distributor in Exeter, N.H. Credit... Herb Swanson for The New York Times

“This could be the winter of our discontent,” said Daniel J. Weiss, a senior fellow at the Center for American Progress. “This is going to have a huge impact. It will start to pinch people in September and October and could influence this fall’s elections. Remember, it is much easier for people to drive less than it is to heat less.”

Consumers are not entirely powerless, of course, and have already started to react to higher energy bills. Gasoline consumption is down by 2.4 percent in the last month, compared with the same period last year, according to the latest figures from the Department of Energy.

Oil futures, which reached a record of $145.29 last month, closed at $119.17 on the New York Mercantile Exchange on Tuesday. Gasoline prices have also declined after reaching a nationwide peak of $4.11 a gallon. Gasoline is now selling for $3.87 a gallon on average, according to AAA, the automobile group.

Heating oil futures settled Tuesday at $3.28 a gallon, down 2 percent. Retail prices can add $1 a gallon or more to futures prices after marketing and distribution costs. “The deteriorating demand picture reinforces our belief that oil prices are approaching a tipping point,” energy analysts at Lehman Brothers said in a report last week. They forecast crude oil prices to average $90 a barrel by the beginning of next year.

With prices still high, policy makers are under pressure to act. While Democrats want to rein in what they see as excessive speculation in commodity markets and have proposed to release some oil from the nation’s strategic reserves, Republicans are pressing to open more areas to offshore drilling. This deadlock has prevented the passage of any energy legislation lately, although many experts say there is little Congress can do to reduce prices in the short term.

“It is one thing if you can’t drive your car, but it is quite another thing if you can’t stay warm on a cold winter night,” said former Representative Joseph P. Kennedy II, the president of Citizens Energy, a nonprofit organization that provides low-cost energy assistance to poor people.