*TSX falls 69.35 points, or 0.5 pct, to 13,366.60
*Nine of 10 index sectors weaker, RIM gains
*CNR top decliner after earnings report (Updates with details, comments)
By Claire Sibonney
TORONTO, July 26 (Reuters) - Toronto's main stock market index drifted lower on Tuesday morning as lackluster Canadian earnings and a stalemate in U.S. debt talks kept many investors on the sidelines.
All three of the index's most heavily weighted sectors were lower: financials fell 0.5 percent, energy slipped 0.5 percent, and materials lost 0.3 percent.
Toronto-Dominion Bank (TD.TO), down 0.8 percent at C$79.57, and Suncor Energy (SU.TO), down 0.8 percent at C$39.13, were among the biggest laggards.
"I just think that it is probably uneasiness with the political situation in the United States," said Fred Ketchen, director of equity trading at ScotiaMcLeod, who noted that U.S. debt worries were taking a toll on commodity prices, which helped pull down stocks.
"That is causing people just to say 'you know, I don't need to be in the market right now'. I'll just take a walk back and stand on the sidelines and wait for something to happen that gives it a reason to rally," Ketchen said.
The United States edged closer on Tuesday to a devastating default as President Barack Obama's Democrats and the Republicans were deadlocked over competing plans to raise the debt ceiling, one week before a deadline to act. [nN1E76P002]
At 10:18 a.m. (1418 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 69.35 points, or 0.52 percent, at 13,366.60. Nine of the 10 main index groups were weaker, while technology shares added 0.3 percent.
Ketchen also pointed to domestic earnings that were only "half decent," and failed to entice investors back into the market.
Canadian National Railway (CNR.TO) was the heaviest decliner, down 2.4 percent at C$73.42, after its report of a modest increase in quarterly earnings on Monday failed to impress investors. [nN1E76K2GN]
Rogers Communication (RCIb.TO) was close behind, dropping 4.5 percent to C$36.12 after reporting an almost flat profit as it fought hard to keep its lead position in Canada's wireless sector. [nN1E76O1QC]
Inmet Mining IMN.TO sank 5.3 percent to C$66.26, after the Canadian base metal miner reported disappointing quarterly results and cut its full-year production outlook due to operational problems. [nN1E76P0BA]
Among the gainers, BlackBerry-maker Research In Motion RIM.TO rose 1.4 percent to C$25.55 following a sharp selloff in the previous session.
($1=$0.94 Canadian) (Reporting by Claire Sibonney; editing by Peter Galloway)