For his Wednesday-night debate with President Obama, Mitt Romney has been advised to be tough but affable. He should put his warm and caring side on display, while picking apart the president's record and rebutting dubious statements by Mr. Obama. "I'd be tempted to go back to that wonderful line by Ronald Reagan, 'There you go again,'" Mr. Romney said last week.

Mr. Romney should do in the debate what he hasn't done in his speeches, media appearances or TV ads—in other words, in his entire campaign. He must make a forceful case that America's survival as a prosperous and respected nation is at stake. In that context, the election becomes an urgent choice between a national turnaround and further decline. The Romney advertising has been especially sorry at drawing that distinction. The generally bland commercials feel like they could have run at any time in the past 40 years.

Voters understand that America is in trouble. For years, they've told pollsters the country is headed in the wrong direction. Today they're even more gloomy. At every focus group I've heard about recently, they agree with the notion that their children will be worse off than they are. A Fox News poll in August found that by nearly a 2-1 ratio voters think American civilization is in decline. In short, faith in the American Dream has tanked.

According to a Rasmussen poll last week, 15% of likely voters are uncommitted or willing to change their vote. "One of the distinguishing features of those potentially persuadable voters is that they don't see the choice between Romney and Obama as particularly significant," Mr. Rasmussen said. "Just 28% say it will be very important which man wins."