Senate Democratic leader warns U.S. going over 'fiscal cliff' By David Lawder and Fred Barbash WASHINGTON (Reuters) - The top Democrat in the Senate warned on Thursday that the United States looks to be headed over the "fiscal cliff" of tax hikes and spending cuts that will start next week if squabbling politicians do not reach a deal. Majority Leader Harry Reid told the Senate in a speech that "it looks like that is where we're headed." He called on the Republicans who control the House of Representatives to prevent the worst of the fiscal shock by getting behind a Senate bill to extend existing tax cuts for all except those households earning more than $250,000 a year. With the House not in session and the clock ticking toward the scheduled January start of tax increases and deep, automatic government spending cuts, Reid offered little hope. "I don't know time-wise how it can happen now," he said. President Barack Obama arrived at Andrews Air Force Base outside Washington after a flight from Hawaii on Thursday on his way back to the White House to try to restart stalled negotiations with Congress. Obama made phone calls to congressional leaders on Wednesday from his vacation in Hawaii to try to revive the stalled talks to prevent the "fiscal cliff" scenario, which would worry world financial markets and could push the United States back into recession. U.S. stocks fell to session lows after Reid's pessimistic remarks. In addition, consumer confidence fell to a four-month low in December as the budget crisis sapped what had been a growing sense of optimism about the economy, a report released on Thursday showed. "People are hearing about (the cliff) and it negatively impacts confidence and investor sentiment and even holiday sales," said Todd Schoenberger, managing partner at Landcolt Capital in New York. The chances of a last-minute deal - at least one that would prevent tax hikes - remained uncertain, with Republicans and Democrats each insisting the other side move first amid continuing partisan gridlock. The Senate, controlled by Democrats, was scheduled to meet later on Thursday but on matters unrelated to the "fiscal cliff." Speaker John Boehner and other House Republican leaders, who say they are willing to take up a "fiscal cliff" measure only after the Senate acts on one, were to hold a conference call with Republican House members on Thursday. Everybody wants their stuff but doesn't want to give up what they don't want to give up," Republican U.S. Representative Steven LaTourette told CNN. Hope persisted that Republicans and Democrats might come up with a resolution before New Year's Day that could at least postpone the impact of the tax hikes and spending cuts while further discussions take place. That gives some hope to world markets. The Treasury Department is to begin "extraordinary measures" to buy time. Additional reporting by Doina Chiacu, Alina Selyukh and Richard Cowan; Writing by Alistair Bell; Editing by Will Dunham