Wednesday, in a videotaped message to a labor group in Las Vegas, an exasperated-sounding Hillary Clinton closed her remarks by saying, “So having said all that, why aren’t I 50 points ahead, you might ask?”

It’s a question Democrats all over the country are asking as the 2016 race heads into the final stretch with their candidate clinging to a small lead over a bombastic billionaire and reality television star. Clinton and her supporters are legitimately bewildered as to why this race is so close.

But it’s not really a mystery. The reasons are plentiful and have been on display throughout the course of the campaign. Let’s start with the millennial generation voters who turned out overwhelmingly eight years ago for Barack Obama and against both Hillary Clinton and John McCain. Why aren’t they feeling as “fired up and ready to go” as they were for Obama? Because they’re still “waiting on the world to change,” in the words of the John Mayer song that they hummed at Obama’s 2008 rallies — and because in the last eight years both political parties have added $9 trillion to the national debt that they are on the hook for.

Hillary Clinton is getting crushed among working-class whites (men in particular) without college degrees. Why? Because most of them haven’t had a raise in the generation since she and Bill arrived in Washington while the Clintons themselves have amassed a personal fortune in public service estimated at $200 million.

She’s also losing independents, most of whom view her ongoing email scandal as reinforcing the view, now held by large majorities of voters, that she’s not honest or trustworthy.

To be 50 points ahead, Hillary would also need considerable support in the grassroots among Republicans. With all due respect to George H.W. Bush, how can she appeal to GOP voters when she refers to Republicans as “enemies,” as she did during the Democratic debate season?

(Alone among the Democrats on stage, Jim Webb gave a literal answer to the question about which enemy they were proud to have made: “I’d have to say the enemy soldier that threw the grenade that wounded me, but he’s not around right now to talk to.”)

Complicating matters even more, Clinton’s greatest strength as a candidate, which is the public’s favorable view of her experience and temperament, also comes with qualifications.

In the latest NBC News/Wall Street Journal poll, 36 percent of respondents said the No. 1 issue that concerned them about Clinton was “her judgments and decisions in dealing with Syria, Iraq, and Libya.” Her use of a private email server while secretary of state was voters’ second biggest concern at 29 percent.

All of this highlights the ongoing dilemma Clinton faces. Her personal history and the cross-currents of this election in an evenly divided and highly partisan nation make it difficult for her to appeal to enough voters to lead her opponent by 10 points, let alone 50. Her biggest lead in the RCP national average, which came right after her convention in Philadelphia, was 7.9 percent.

Her task would be difficult for a great politician, let alone someone with Clinton’s baggage. To paraphrase then-Sen. Obama’s backhanded compliment of her during a debate in 2008: She’s likable enough. But just barely — and only because her opponent is even less likable in the eyes of so many voters. But she doesn’t need to win by 50 points, she only needs to win by one, and that X-factor — Donald Trump’s own baggage — is why she’s ahead at all.

Tom Bevan is co-founder and publisher of RealClearPolitics and the co-author of “Election 2012: A Time for Choosing.” Email: tom@realclearpolitics.com, Twitter: @TomBevanRCP This commentary is reprinted with permission from RealClearPolitics.