Poor Hillary Clinton.

Not only does the Democratic nominee, not known for her soaring rhetorical skills, have to follow a pair of stem winders from President Obama and Vice President Biden Wednesday night. She must also feel mighty tempted to walk back some of the happy talk they dispensed, which the public shows little if any sign of believing.

The central tension in this election on the Democratic side has been acknowledging the deep public dissatisfaction with where things stand for America in 2016, while not actively tarnishing the legacy of the Democratic president of the past 7.5 years. That has been especially true for Clinton, who has effectively been running for his third term. She had to do that to keep the Obama coalition intact, but hardly anyone outside that group -- nor many of the hard-left Democrats attracted to Bernie Sanders' candidacy -- is sure that's such a good idea.

As I noted last week in a post about the "dark" picture Donald Trump painted in his own convention speech, two-thirds of Americans believe the country is on the wrong track -- with a 44-point gap between the percent saying wrong track and those saying right track. That's an average of polls. One pollster that has been asking the same question over time is Gallup , and here's how its current figure compares to those at the same stage of the past several presidential elections and how the party in control of the White House at the time fared:

1992: minus-63; lost

1996: minus-19; held

2000: plus-26; lost

2004: minus-16; held

2008: minus-64; lost

2012: minus-41; held

2016: minus-65; ??

(Note: In 1988 and before, Gallup did not ask this question at this time of year.)

Now, first of all, that track record demonstrates it's difficult for a party to win three straight presidential elections; in fact, the GOP's three wins from 1980-88 are the only time it's happened since Truman made it five in a row for the Democrats in 1948. It also demonstrates why: By the end of two terms by one party, the country tends to feel the need to go in a different direction.

Nothing about that data, including the low feelings Americans currently hold, indicates the Democrats should win a third straight term. Their hope hinges on the notion Trump is not only dangerous and unpredictable, but pessimistic. On Wednesday, Biden and Obama tried to counter that not only by portraying Clinton as safe and steady, but by making it seem extra sunny in Philadelphia.

"(W)hile this nation has been tested by war and recession and all manner of challenge," Obama declared, "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. How could I not be, after all we've achieved together?"

That may come as cold comfort to those who are still without work (years after the recession ended, millions of working-age Americans remain out of the labor force ) or who are earning less than before (real median household income remains 6.5 percent below the 2007 level ). It sounds discordant to those who by 2008 had come not to expect another terrorist attack on the homeland, and who now read about lethal ISIS attacks on Americans or some of our closest allies with alarming frequency, while the current administration seems too inept to prevent them . It rings hollow to those who went from having low-cost health insurance plans that denied their claims to high-cost insurance plans that set high deductibles before they'll start paying for claims. It beggars belief who have watched shooting by and of police officers become staples of our news headlines .

It's not "fear mongering" or unpatriotic to point out those kinds of things, or at least Democrats didn't think so in 2004 or 2008.

Understandably, Obama doesn't want to be remembered for those things. But we aren't voting for a political epitaph this November; we're electing someone to deal with the real problems we face.

If Hillary Clinton is too realistic about our problems, she risks alienating Obama voters. If she is too blase about them, she risks being dismissed by independents. Whether she can thread the needle tonight will go a long way toward determining the trajectory of this race in the weeks to come.