U.S.stocksfell, with the Standard & Poor’s 500 Index sliding for a second day, as growing tension over possible military action inSyriaovershadowed a report showingconsumer confidenceunexpectedly rose in August. TheDow Jones Industrial Averagedropped 126.86 points, or 0.9 percent, to 14,819.60. European stocksslid the most in nine weeks. Emerging-market stocks posted the biggest drop in eight weeks. Investors are also watching the political wrangling over the approaching limit on federal spending. The U.S. government is expected to exhaust its ability to borrow funds in mid-October. Southwest dropped 3.5 percent to $12.81. United Continental Holdings Inc. plunged 7.4 percent to $27.66 and Delta Air Lines Inc. slumped 6.3 percent to $19. Best Buy Co. lost 2.1 percent to $35.05. Richard Schulze, the electronics retailer’s founder and largest shareholder, said he plans to sell an undisclosed amount of its stock to diversify his assets and raise money.