The simple reason that Joe Biden must run for President of the United States is that almost all the other Democratic candidates are so radical that only Biden can stop the party from taking itself — and perhaps the country — off a cliff.

That thought occurred to me as I covered a rally by socialist Sen. Bernie Sanders (I-VT) in Los Angeles last week.

Sanders currently leads the polls among declared 2020 candidates for the Democratic Party nomination. His rhetoric is radical, and his supporters are as well.

What Sanders says from the podium is nothing compared to the radicalism of the Sanders staff — some of whom are illegal aliens — and some of Sanders’ eager supporters.

Worse, Sanders’s rivals are just as bad. In 2016, his ideas were considered crazy; in 2019, they are being embraced by nearly all of the candidates, though they are no more practical today.

Sander championed “Medicare for All,” for example, and openly admits that the policy would ban private insurance, meaning tens of millions of Americans would lose the coverage they currently have and be forced to accept government insurance. Only 15% of Americans support such a plan, but most of the House Democrats support it, as do many of the presidential candidates, including fellow frontrunner Sen. Kamala Harris (D-CA).

The “Green New Deal,” which Sanders also backs, along with almost all of the Democrats running, is a socialist mess so extreme that even solar and wind power companies are avoiding it. The Senate voted on it this week, and it was rejected unanimously, with most Democrats — including all of the co-sponsors and presidential candidates — voting “present.” Its inventor, Rep. Alexandria Ocasio-Cortez (D-NY), is less popular than Trump in her own state.

On foreign policy, Sanders has views that are largely unchanged from those of the Cold War, when he cavorted in the Soviet Union on his honeymoon. (As Sen. Lindsey Graham (R-SC) joked in 2015, Sanders “went to the Soviet Union on his honeymoon and I don’t think he ever came back.”) Sanders is leading the charge to protect Venezuelan dictator Nicholas Maduro. Some of his advisers are also not just anti-Israel, but also antisemitic in their criticism.

There, too, the rest of the field has followed Sanders’s lead to the left. Not one elected Democrat attended the opening of the U.S. embassy in Jerusalem last year, and not one Democratic presidential candidate attended the annual American Israel Public Affairs Committee (AIPAC) conference this week (though a few met with pro-Israel lobbyists in their offices on Capitol Hill). Pro-Israel Democrats are privately beginning to panic about their party.

Analysts currently expect Democrats to have a good chance of winning the White House. But the radicalism of the Democratic candidates could make a winnable election a shoo-in for Donald Trump. And if Democrats do win, they will bring in an administration committed to the most radical socialist policies any country will have enacted since the fall of communism.

The results for the United States, and for the world in general, could be devastating.

Biden has many flaws, and has never done well running for president on his own. The former vice president also has questions to answer about questionable dealings in China involving his son. And he has spent the past several weeks apologizing for perceived past misdeeds on race and gender.

But Democrat donors must be beating down his door. The party needs him to run. And so, too, does the country. His Democratic rivals are is looking scarier each day.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.