Once again, it was mission impossible. And once again, it was mission failure.

Bernie Sanders is still standing. Time is running out to stop him.

In their debate last week, the other Democrats aimed to make themselves his top rival for the nomination by viciously attacking each other. The net effect was that they were all damaged and Sanders waltzed to a smashing win in the Nevada caucus.

On Tuesday, the other Dems had the same goal, but went about it differently. This time, they mostly attacked Sanders directly while largely ignoring each other.

They landed some blows, but nothing decisive. Sanders was a man confident of his support and positions and the attacks failed to knock him off balance.

We’ll know for sure Saturday when South Carolina voters have their say, but it’s highly likely that the Democrat Socialist will retain his spot as the party’s front-runner. What a world.

Michael Bloomberg, in his second debate, acquitted himself better than in his first, but that was a low hurdle. Even still, he made some blunders and seemed to lose energy as the night wore on, realizing he hadn’t succeeded in either pulling down Sanders or lifting himself up.

He came prepared with what he thought was an opening zinger, but it bombed. Looking at Sanders, he said that “Russia is helping you get elected so you’ll lose” to Donald Trump.

It was a puzzling, cringe-worthy start and it fell flat with the audience. Whatever Bloomberg is paying for debate prep, it’s too much.

He also took a lot of incoming, with moderators asking his rivals if his stop-and-frisk policy in New York was racist. It was, they said, but once again Sen. Elizabeth Warren stood out for her slashing assaults on Bloomy.

She sought out chances to hammer him, so much so that it was either gratuitous or she was trying to protect Sanders. The speculation that she could be his running mate certainly seemed plausible by the way she did much of his dirty work against his top rival.

Asked why she had called Bloomberg the “riskiest” candidate, Warren said that “the core of the Democratic party will never trust him.”

She’s almost certainly right, notwithstanding that Bloomberg has been spending prodigious amounts of money to prove her wrong. To judge from his grim demeanor, reality may be sinking in.

Of course, he can afford to stay in the game, but his argument that Sanders has too narrow a base to win the general election, even if true, doesn’t change the fact that Bloomberg’s base is even smaller. So is everybody else’s.

For Joe Biden, it was another strange night. Shouting and full of stammering, he said that 150 million people had died from gun violence in America since 2007.

Everybody was too kind to correct him, which means they pity him more than they fear him. Unless he wins Saturday, his race will be over. The same fate likely awaits Sen. Amy Klobuchar and Tom Steyer.

With the field shrinking, Sanders, the 78-year-socialist, would be a prohibitive favorite to win the nomination after just four states. Facing fewer contenders, his delegate haul would grow larger and faster in the crucial March primaries.

His supporters are not half the Democratic Party, but they are the most committed and energized.

Asked why they support him, many tell reporters that they find him “authentic.” As evidence, they cite the fact that he’s been saying the same things for 40 or 50 years.

They mean this as a compliment and no doubt many have Hillary Clinton in mind. She was a shape-shifter of historic proportions and, thus, the least authentic presidential candidate in memory.

Pete Buttigieg, Elizabeth Warren and Bernie Sanders
Pete Buttigieg, Elizabeth Warren and Bernie SandersAP

That she beat Sanders for the nomination four years ago, then lost to the extra-authentic Donald Trump, apparently taught Sanders’ followers that authenticity is everything.

That could explain why they are less concerned about the kooky things he believes than the fact that he truly believes them.

But think about a man who hasn’t changed his position on such fundamental things as socialism, communism and capitalism for 40 or 50 years. Authenticity isn’t the only or best way to describe such a man.

Arrested development is more accurate.

Life is the best teacher, learn at the school of hard knocks and similar nostrums all express the common-sense fact that character develops through the experience of living. Riding the waves of joy and sorrow, overcoming setbacks and building lasting relationships are matters of trial and error and hopefully lead to sound judgment and even wisdom as we grow older.

Yet we are to believe that Sanders has been immune to his personal experiences and everything that has happened in the world in the last half-century. His mind was fixed in the 1960’s and never did he reconsider his youthful enthusiasms for the Soviet Union, Cuba and other nations run by murderous socialists and communists.

The Castro regime, for example, has brutalized the Cuban people and turned the island into a police state. An impoverished one at that.

Assassination by government was common and dissenters are still locked up. The freedoms that Americans take for granted — speech, religion, upward mobility, choice of schools, homes and occupations — have been denied Cubans for more than six decades.

Property is owned by the government, so you can’t really buy a house or sell one — unless the government grants you a favor.

Yet Sanders to this day defends the Cuban revolution, citing its “literacy program,” as if the trade-off is worthwhile.

While he claimed Tuesday he has been denouncing authoritarianism his whole life, it is a fact that he has said nicer things about Fidel Castro than Trump, and lavished more praise on Cuba and the Soviet Union than on the United States.

Who thinks that way?

Sanders does, but more to the point at hand, who thinks such a closed, warped person would make a good president of the United States of America? That millions of people do is the really frightening part of what is happening among Democrats.