President Trump has been enduring the worst scandal of his presidency over the past two weeks, following evidence from both himself and a whistleblower that he attempted to coerce Ukraine into investigating the family of his top political rival, Joe Biden.

So naturally, Trump has doubled and tripled down. In an impromptu press conference outside the White House Thursday, Trump publicly called once more for not only Ukraine but China to investigate the Bidens — just after he laid out an explicit threat: "I have a lot of options on China, but if they don't do what we want, we have tremendous power," he said.

Trump is very obviously abusing his presidential power to try to rig the 2020 election. And most of what Trump says is lies — his conversation with the Ukrainian president was premised on an absurd conspiracy theory designed to excuse Russian election meddling and flatter Trump's fragile ego.

But equally obviously, Joe Biden is horribly unsuited to be the Democratic standard-bearer in this election. Biden and his family have been at least peripherally involved in scummy, corrupt stuff across the world. Nominating him would seriously foul up Democratic messaging about Trump.

Now, it's important to emphasize again that all investigations of Trump's specific allegations about the Bidens have found them to be false. There is no evidence that Vice President Biden went to Ukraine to bail out his son Hunter by pressuring that government to fire their top prosecutor — on the contrary, as famed investigative reporter James Risen (who originally broke the story) writes at The Intercept, the replacement prosecutor was harder on the company in question, Burisma Holdings, not easier.

It's also important to note that whatever the Bidens have done, the Trump family has done an order of magnitude worse. A few examples at random: Jared Kushner's hedge fund is reportedly seeking an investment of $100 million from a fund largely backed by Saudi Arabia and the U.A.E. — something he almost certainly would not be getting as a private citizen. While touring India last year, Donald Trump, Jr. was openly soliciting $38,000 bribes. Ivanka Trump apparently leveraged her White House connections to get several patents in China. (Full details of all the Trump family self-enrichment during his presidency is going to take several books.)

That said, it is absolutely inconceivable that Hunter Biden was hired by Burisma — at a cool $50,000 per month — for his expertise in Ukrainian geological formations. At the time, he had just washed out of the Navy Reserve for failing a cocaine test. He got hired for his connections, obviously. Companies the world over keep failsons of the rich and powerful on their boards just in case it might pay regulatory or geopolitical dividends. It's just the price of doing business in a monumentally corrupt age.

Or take Trump's accusation that Biden lied about not talking to Hunter about his businesses, in a video which displays a picture of Joe, Hunter, and a third man labeled "Ukraine gas exec" on a golf course. The third man is Devon Archer — an American who has worked with Hunter for years, but also sat on the board of Burisma Holdings. It doesn't prove that Biden lied about not talking business with his son (after all, they could have just chatted about sports and whatnot while golfing), but it does provide another association between Biden and scummy Ukraine stuff.

Or take Trump's accusation that Hunter pocketed a quick $1.5 billion from some Chinese investment fund. This is completely false — indeed, from all appearances, Hunter made no money on the venture at all — but he did help create a fund in China while his father was vice president, and it was still ethically suspect. "In countries like Ukraine and China, regardless of what Hunter Biden might think or say, people want to do business with him almost entirely because of who is father is," Columbia University's Lincoln Mitchell told PolitiFact.

Hunter Biden is simply part of the rat's nest of corruption, logrolling, and favor-trading that winds through the globe-spanning plutocratic elite. And you can see why it might not even have occurred to the Bidens that this kind of thing is morally suspect. Barack Obama himself has scarcely been better, with his post-presidential buckraking career of speeches before Wall Street banks at $400,000 a pop — after stubbornly refusing to prosecute a veritable container ship-load of financial crimes by big banks as president.

Only chumps like Jimmy Carter forswear the hustle and live modestly — that is, just scraping by on a piddling $210,700 presidential pension, plus occasional floods of book revenues. What is an ex-president supposed to do, serve as some kind of moral example of republican virtue? How are you supposed to go windsurfing with Richard Branson if you act like Cincinnatus?

Liberals often get furious when you criticize their favorite leaders for being money-grubbing scoundrels who let their kids trade on their name. But nominating Biden would be a political grenade that explodes right in the middle of Democratic messaging about why Trump should be impeached and defeated in 2020. Instead of a clean, simple message the Democrats are clean and Republicans are corrupt, they would be forced into complicated arguments that Biden's history isn't as bad, or tendentious, unconvincing arguments that it isn't bad at all. (Sound familiar?)

It would be so much easier and simpler to have someone else leading the party as the 2020 general election gets started. Biden can be a clear victim of Trump's abuses of power, but not his replacement.

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