The Bush administration is confident that Afghanistan's first direct presidential election will be deemed fair and valid despite protests from candidates that the balloting was marred by fraud, a top presidential aide said Sunday.

"This was an extraordinary day for the Afghan people, and this election is going to be judged legitimate," said President Bush's national security adviser, Condoleezza Rice (search). "I'm just certain of it."

All 15 challengers to U.S.-backed interim President Hamid Karzai (search), strongly favored to win, announced Saturday they would boycott the election's outcome because the ink used to mark some voters' thumbs could be rubbed off too easily. They contended this allowed people to vote multiple times.

"Clearly, there were some technical difficulties with the ink system," Rice said on "Fox News Sunday." "Obviously, there are technical difficulties sometimes even in the mature democracies when it comes to elections. And people have the right to challenge."

In the end, Rice said, "there will be a mechanism to resolve these concerns within the context of the Afghan election law." She added: "the United Nations (search) and the Afghan Electoral Commission (search) have said that they do not believe that these technical difficulties fundamentally would have changed the nature of the election."

Appearing on a network news show, Democratic vice presidential candidate John Edwards (search) did not question the legitimacy of Saturday's historic election. He did, however, say that war-ravaged Afghanistan is far from the flourishing democracy that Bush has portrayed time and time again on the campaign trail.

"If you look at what's actually happened in Afghanistan since the Taliban (search) was toppled, their opium production is back up. They're producing 75 percent of the world's opium," Edwards said.

"On top of that, there are big chunks of the country still in the control of warlords and drug lords, and there are still some serious security issues in the country," he added.

U.N. surveys estimate Afghanistan accounted for three-quarters of the world's opium last year. The trade brought in $2.3 billion — more than half of the nation's gross domestic product.

Edwards said the United States needs to do more to fight the opium problem. On a different network television show, he suggested teaming up with the British to double the counternarcotics (search) effort "so that we don't continue to see this expansion of their drug trade." The British military has taken the lead in the anti-narcotics effort in Afghanistan.