For all his appeal as a speaker, and for all the love coming from Democrats crowded inside the Wells Fargo Arena, President Obama made a classic mistake in his address to the Democratic convention Wednesday night. Determined to defend his own accomplishments in office as well as convince Americans to elect Hillary Clinton for what would amount to his third term, Obama painted a picture of life in the United States that was brighter and more positive than most voters believe.

“While this nation has been tested by war and recession and all manner of challenge �?? I stand before you again tonight, after almost two terms as your president, to tell you I am even more optimistic about the future of America,” Obama said.

“How could I not be �?? after all we’ve achieved together?”

In the most recent NBC/Wall Street Journal poll, 73 percent of registered voters said the country is on the wrong track, while just 18 percent said it is headed in the right direction. The 73 percent figure is the second-highest in the president’s nearly eight years in office.

The poll was no outlier. These are the wrong-track numbers for the last ten polls in the RealClearPolitics average of polls: 67, 70, 67, 71, 73, 69, 79, 68, 60 and 66.

And yet, in spite of clear evidence that a majority of Americans believe the U.S. is headed in the wrong direction, the president exhorted the nation, “Thank you for this incredible journey �?? let’s keep it going.”

Obama spoke as if broad areas of American life are better than ever, even if there remains work to be done. When Obama said, “My time in this office �?? it hasn’t fixed everything,” the millions of voters who believe the country is on the wrong track might have seen that as a significant understatement.

“By so many measures, our country is stronger and more prosperous than it was when we started,” Obama said. On one hand, that is true for some Americans, given the depths of economic distress the country was entering in January 2009. But on the other hand, even with terrible economic conditions, the percentage of Americans who believed the country was on the wrong track went down dramatically in Obama’s first months in office �?? it fell to 43 percent in April 2009 �?? because many people had faith in Obama to make things better. Today, with the wrong track number 30 points higher, they no longer believe.

But in Philadelphia, Obama pushed the positive. “The America I know is full of courage, and optimism, and ingenuity,” he said:

The America I know is decent and generous. Sure, we have real anxieties �?? about paying the bills, protecting our kids, caring for a sick parent. We get frustrated with political gridlock, worry about racial divisions; are shocked and saddened by the madness of Orlando or Nice. There are pockets of America that never recovered from factory closures; men who took pride in hard work and providing for their families who now feel forgotten; parents who wonder whether their kids will have the same opportunities we had. All that is real. We’re challenged to do better; to be better. But as I’ve traveled this country, through all 50 states; as I’ve rejoiced with you and mourned with you, what I’ve also seen, more than anything, is what is right with America. I see people working hard and starting businesses; people teaching kids and serving our country. I see engineers inventing stuff, and doctors coming up with new cures. I see a younger generation full of energy and new ideas, not constrained by what is, ready to seize what ought to be.

The question in the general election campaign is whether voters buy Obama’s optimism enough to elect his designee Clinton. “Hillary’s biggest obstacle to being elected [is] the fact that three-quarters of the voters believe the country is headed the wrong direction,” said Republican strategist Curt Anderson this week. “The wrong track is a ball-and-chain on her campaign.”

As Obama spoke, a number of Republicans who oppose Donald Trump argued that Obama, not Trump, had captured the essential optimism of Ronald Reagan. “It’s morning in America at the DNC convention. They stole the Reagan sunniness,” tweeted former Jeb Bush aide Tim Miller, who in recent months has worked in the “Never Trump” effort.

But it’s not at all clear that sunniness will work for Obama. In 1980, Ronald Reagan was not burdened with trying to defend a two-term presidency at a time when Americans had grown deeply disillusioned; he was the opposition party candidate asking unhappy voters to give him a chance to govern. And in 1988, when Reagan had served two terms and George W. Bush was campaigning for Reagan’s third, the percentage of people who felt the country was on the wrong track was in the low 40s �?? far lower than it is today. Optimism did not seem out of place.

In Philadelphia, Obama gave the audience a greatest hits tour from 2004, when he first rose to national prominence with a speech at that year’s Democratic convention. “You’re who I was talking about 12 years ago, when I talked about hope,” Obama said. “It’s been you who’ve fueled my dogged faith in our future, even when the odds are great; even when the road is long. Hope in the face of difficulty; hope in the face of uncertainty; the audacity of hope!”

Has Obama’s act worn thin? While he is, at the moment, moderately popular, there remain those millions of Americans for whom life hasn’t gotten better. Will they buy a message of optimism from the same people who have been in charge for the last eight years? Hillary Clinton’s future is riding on that question.