LONDON — When Mariel Zagunis carries the United States flag into Olympic Stadium tonight, the fencer said she would have only one objective. "I'm going to focus on not tripping," she said, "and not letting the flag touch the ground."

LONDON — When Mariel Zagunis carries the United States flag into Olympic Stadium tonight, the fencer said she would have only one objective. "I'm going to focus on not tripping," she said, "and not letting the flag touch the ground."

But will the two-time Olympic gold medalist dip the flag when she passes in front of the British heads of state? The U.S. is among the few nations that do not make that gesture during the athletes' entrance at the Olympics, a tradition that historians say began in London at the 1908 Summer Games. According to one version of the story, U.S. track athlete Ralph Rose refused to dip the flag before King Edward VII, saying, "This flag dips to no earthly king."

The Olympics' return to London raised the issue again this week, though it was hardly the biggest flap involving a flag. Despite the insistence of officials and athletes that the Olympics should transcend politics, the two inevitably intersect, often in uneasy fashion. That was underscored multiple times Thursday as London made final preparations for today's opening ceremony.

The London Organizing Committee of the Olympic Games apologized to North Korea for mistakenly showing the South Korean flag on the scoreboard as its women's soccer team was introduced. Republican presidential candidate Mitt Romney said it was "hard to know just how well" the Olympics would fare in London, then backtracked from those remarks later in the day. The U.S. Olympic Committee (USOC) issued a statement demanding that American political groups stop using Olympic imagery in attack ads.

Thursday brought plenty of joy and anticipation as well, with thousands gathering to watch the Olympic torch being paraded past landmarks such as Buckingham Palace and Hyde Park. Prime Minister David Cameron promised the Opening Ceremony would include some "spine-tingling" moments.

USOC chief Scott Blackmun said his organization had been discussing the flag dip but did not seem concerned about any fallout. "We have traditions," he said. "Britain has traditions. Everybody has traditions. We're still talking internally, but I don't think it's a big issue."

There did not seem to be any lingering hard feelings about Romney's remarks. Blackmun said the American delegation's experience in London had been "nothing but positive," a sentiment echoed by many athletes Thursday.