* TSX falls 34.36 points, or 0.28 percent, at 12,134.48 * Canadian Natural off 2 pct after outlook fails to impress * Eight of 10 main sectors decline By John Tilak TORONTO, Dec 4 Canada's main stock index fell on Tuesday, led by a drop in Canadian Natural Resources Ltd on concerns about its 2013 outlook, while the overall market continued to fret about whether U.S. politicians would be able to resolve the country's looming fiscal crisis. Shares of Canadian Natural fell 2 percent to C$27.60 despite a bullish price forecast for the company's oil-sands crude, as investors had expected more substantial production growth, analysts said. "Evidently the market felt that was a little disappointing," said Gavin Graham, president of Graham Investment Strategy. The energy sector, which played the single biggest role in leading the index lower, was down 1 percent, tracking lower oil prices. Other oil and gas producers declined in sympathy with Canadian Natural, with Encana Corp down 2 percent at C$21.19 and Nexen Inc falling 1.8 percent to C$24.22. "You're seeing a combination of micro, company-specific issues and macroeconomic issues putting pressure on the energy sector," said Craig Fehr, Canadian market strategist at Edward Jones in Missouri. "Investors are looking at the global growth story, realizing that it's continuing to weigh on external demand, particularly for resource exports that will come out of Canada," he said. But the broader concern for investors was the risk that U.S. politicians would fail to reach a deal to prevent the trigger of automatic government spending cuts and tax increases in early 2013 from tipping the economy back into recession. President Barack Obama said on Tuesday there is not enough time this year to come up with an overhaul of the U.S. tax system and entitlement programs that Republicans want as a condition for an agreement to avoid the so-called "fiscal cliff." "It's as bad as the NHL hockey discussions. Both sides have hardened their positions when there were expectations of hope," said John Ing, president of Maison Placements Canada. "They're running out of time. There is maybe a week left before something meaningful can be done. It is a worry," he added. The Toronto Stock Exchange's S&P/TSX composite index was down 34.36 points, or 0.28 percent, at 12,134.48 by mid-afternoon. Eight of the 10 main sectors on the index declined. ShawCor Ltd was the fourth biggest drag. The energy services company shed 15.3 percent to C$38.91 after it said it was unlikely to sell itself following a review of strategic alternatives that it had undertaken. Bank of Montreal gained 0.6 percent to C$59.66 after Canada's fourth-largest lender reported a 41 percent rise in quarterly profit, topping estimates, as wholesale banking income doubled and loan-loss provisions plunged. Goldcorp Inc was up 1.8 percent at C$37.95, and Barrick Gold Corp rose 0.7 percent to C$33.83, helping the materials sector, which includes mining companies, to advance 0.2 percent.