Democrats thought that anger over the Iraq war would drive them to victory. What happened?

It's hard to say that the situation in Iraq has improved—not with the death toll of Americans having climbed above 1,000. But public concern over Iraq has declined. Since mid-July, the percentage of Americans who say Iraq will be the most important issue in their vote dropped from 27 to 20 percent in Gallup polling. Iraq is now overshadowed by terrorism.

They are very different issues. Voters whose top concern is Iraq favor John Kerry (56 to 40 percent). Those whose top concern is terrorism overwhelmingly favor President Bush (87 to 13 percent). Bush's issue, terrorism, has pushed Kerry's issue, the war in Iraq, aside. The handover of authority in Iraq at the end of June apparently had exactly the effect that the White House intended: It made Iraq seem like less of an American problem.

Republicans used their convention to argue that Iraq is part of the war on terror. Nobody talked about weapons of mass destruction. But several speakers linked Iraq to 9/11. "Do I forget the lessons of September 11 and take the word of a madman," Bush asked, "or do I take action to defend our country?"

Denouncing Kerry's criticism of the pre-emptive war in Iraq, Vice President Cheney said, "He declared at the Democratic convention that he will forcefully defend America after we have been attacked. My fellow Americans, we have already been attacked." But not by Iraq, critics respond.

Before the Republican convention, polls showed the public split over whether the war in Iraq was a mistake. Since the convention, majorities in every poll (Gallup, CBS News, Washington Post/ABC News, Time) say it was not.

Kerry has done his part to lose the advantage on Iraq. Last month, he dismayed supporters when he answered the president's challenge to say whether he would still have voted to go to war knowing what he knows now. "Yes, I would have voted for the authority," he told a reporter on August 9. Kerry has spent a lot of time since then explaining his position and, some would say, digging himself into a deeper hole. "George W. Bush was wrong again today on Iraq. He claims that I have the same position as he does," Kerry said on September 6. "When it comes to Iraq, I would not have done just one thing differently. I would have done everything differently from this president."

Bush was quick to respond. "After saying he would have voted for the war even knowing everything we know today, my opponent woke up this morning with new campaign advisers and yet another new position. Suddenly, he's against it again," Bush said. A few days later, he escalated the attack. "One thing about Senator Kerry's position is clear," Bush said on September 10. "If he had his way, Saddam Hussein would still be in power and would still be a threat to the security of America and the world."

Bush has finally found a way to turn Kerry into the opponent he always wanted: Howard Dean.

The presidential race is a choice between two fears: fear of the unknown, and fear of the known. Kerry, like all challengers, is running on fear of the known. "This president rushed to war without a plan to win the peace," Kerry charged, "and he's cost all of you $200 billion that could have gone" to schools, health care, prescription drugs, Social Security.

The Republicans' answer? Fear of the unknown. "If we make the wrong choice," Cheney warned, "then the danger is that we'll get hit again, and that we'll be hit in a way that will be devastating." In other words, elect Kerry and you could get killed.

Democrats were outraged. "Dick Cheney's scare tactics crossed the line," John Edwards charged. "This is un-American." Perhaps, but it's not unheard of. Fear tactics often work against a largely unknown challenger. In 1964, for example, GOP presidential nominee Barry Goldwater was hit by President Johnson's famous "daisy" ad. The message: Elect Goldwater and you could get nuclear catastrophe.

President Carter tried the same thing against Ronald Reagan in 1980. Carter charged that Reagan's "radical and irresponsible course would threaten our security and could put the whole world in peril." In 1984, the Reagan re-election campaign turned the argument against the Democrats with the "bear in the woods" ad: "Isn't it smart to be as strong as the bear?"

Fears had shifted, from Republican recklessness to Democratic weakness. Republicans again exploited fear of weakness in 1988 with an ad showing Democrat Michael Dukakis in a tank: "Now he wants to be our commander-in-chief. America can't afford that risk."

Scare tactics work if they are based on real concerns about a candidate: Goldwater as trigger-happy, Dukakis as wimpy. Are there concerns about Kerry?

In a Newsweek poll, 38 percent said the United States would be more vulnerable to attack if Kerry were elected, while 20 percent said the country would be more vulnerable with Bush as president and 35 percent saw no difference. When the ABC/Post poll asked which candidate would keep the country safer, voters preferred Bush to Kerry by nearly 20 points (54 to 35 percent).

The concern about Kerry's steadfastness is out there. And it has displaced concern over the war in Iraq.