Probably my favorite Barack Obama campaign story involves an outdoor speech on a sweltering 2012 day in Roanoke, Virginia. As he went on and on, members of the adoring crowd began fainting from the heat.

The president’s revealing response was not to cut his remarks short and let everyone seek a cold drink and air conditioning.

No, the president of the United States began issuing advice to crowd members on how to avoid fainting so he could finish his remarks. Don’t lock your knees, he said. Don’t stand on just one leg. Drink water. And he assured everyone that paramedics were on the way.

Then, Obama resumed his speech and continued to the very end.

Obama’s speeches were about him back then. And they’re about him today.

Monday in Las Vegas, the ex-president was invited to speak in support of Democrat candidates, who seem to be stumbling in many places in what was supposed to be a walk-away election campaign against President Trump’s Republicans.

Elections are also supposed to be about the future. Democrats seeking seats in Congress have not offered much of a national program because they have none, save to rescind last December’s GOP tax cuts.

And, of course, they denounce Donald Trump. But don’t talk about impeaching him because that would surely spur GOP turnout.

Nancy Pelosi has become a toxic political personality, even among some in her own House caucus. Here’s how she plans on going after him, assuming she becomes Speaker again.

Joe Biden is trying — very trying — to help his party and himself for 2020. But he’ll be 77 for that election. Bernard Sanders is already that old.

So, Obama is the party’s sole remaining star. As is his habit, Obama referred to himself and his administration and his achievements dozens of times. He seemed particularly rankled about Trump taking credit for the current economic boom starting last winter after he signed major tax-cut legislation.

Obama urged his audience to “remember who started” the boom. He added:

When I walked into office 10 years ago, we were in the middle of the worst economic crisis of our lifetimes.

By the time I left office, wages were rising, the uninsured rate was falling, poverty was falling, and that’s what I handed off to the next guy.

Then, the ex-president turned to himself again.

“Unlike some,” he said, “I actually try to state facts. I believe in facts. I believe in a fact-based reality, fact-based politics. I don’t believe in just making stuff up. I think you should actually say to people what’s true.”

Like how a YouTube video caused four American deaths in Benghazi, how his eight-year administration had no scandals and how under Obamacare, all Americans would save $2,500 per household and could absolutely keep their existing doctor and health insurance.