“Self-serving and not credible.” At Tuesday’s public hearing in the House impeachment inquiry, former U.S. envoy Kurt Volker offered that assessment of allegations that former Vice President Joe Biden and his son, Hunter Biden, may have engaged in corrupt self-dealing in Ukraine.

At Tuesday’s marathon session in Intelligence Committee proceedings, that continue on Wednesday and Thursday, other witnesses were invited to testify that they knew of no basis to believe Ukrainian officials had interfered in the 2016 election. Indeed, Democrats continued to press their disingenuous storyline that Ukraine could not have meddled in our presidential campaign because Russia did, as if it were not possible that both countries meddled – as it is virtually certain that both did, on opposite sides.

There has been a common thread in the testimony on these two subjects, potential Biden corruption and 2016 Ukrainian collusion with Democrats: There is no basis to believe, and none has been offered, that the witnesses Democrats permitted to be called have any relevant information about these matters.

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This testimony would not be allowed in a court proceeding under rules of evidence and due process, where witnesses are permitted to address only matters about which they have direct knowledge. If they only know what they’ve read in the papers, their testimony isn’t any more reliable than ours would be.

This is why, for all the formal trappings and somber tones, Democrats are running a kangaroo court.

The hearings are taking place under one-sided rules that enable Chairman Adam Schiff, a fierce partisan, to determine which witnesses are permitted to testify.

Republicans have asked to call such witnesses as Hunter Biden, Nellie Ohr, and Alexandra Chalupa. Biden the younger was lavishly compensated by a Ukrainian energy company, Burisma, while his father was running Obama administration Ukraine policy and demanding that Kiev fire a prosecutor who was investigating Burisma.

Ohr was a researcher at Fusion GPS, the Clinton campaign opposition research arm that produced the bogus Steele dossier.

She testified in a 2018 House investigation that Fusion’s informants included Ukrainian parliamentarian Serhiy Leshchenko – an overt Clinton supporter.

In late 2018, a Ukrainian court found the Leshchenko and an official of Ukraine’s anti-corruption police meddled in the 2016 American election by, among other things, leaking information damaging to Trump campaign chairman Paul Manafort – who was forced to resign. Leschchenko was reportedly also a source for Chalupa, a Ukrainian-born DNC consultant and Hillary Clinton supporter.

For all the formal trappings and somber tones, Democrats are running a kangaroo court. The hearings are taking place under one-sided rules that enable Chairman Adam Schiff, a fierce partisan, to determine which witnesses are permitted to testify.

Schiff has denied Republicans the opportunity to call these witnesses, just as he has denied the GOP the ability to ask questions about the so-called whistleblower who instigated the Ukraine impeachment push (a CIA official who is known to have consulted with Schiff’s staff while preparing his complaint).

According to Schiff, the Republicans must not be permitted to question their preferred witnesses because possible Biden corruption and Ukrainian interference in the election for the benefit of Hillary Clinton are not relevant topics. The only matter in focus is President Trump’s dealings with Ukraine’s government – i.e., the slow-walking of defense aid to pressure Kyiv to conduct investigations “that would benefit Trump politically.”

This, of course, is absurd. In their tunnel vision, what Democrats call the investigations that “would benefit Trump politically” are precisely Biden corruption and Ukrainian meddling in the 2016 election.

Schiff & Co. mulishly insist that Trump was motivated by nothing other than his political fortunes in the 2020 campaign. Obviously, if the fact-finding inquiry is legitimate, the president and Republicans must be entitled to try to demonstrate that Trump had proper motivations.

Contrary to Schiff’s deceptive claim at the start of the inquiry (in his “parody” version of the July 25 Trump-Zelensky phone call), the president was not asking Ukraine to “make up dirt on my political opponent.” There was abundant good-faith reason to suspect self-dealing by the Bidens.

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There is, similarly, a bounty of evidence of Ukrainian interference in the election. The president reasonably contends that his interests were not so much in the politics of 2020 as in accountability for election-meddling in 2016 – a matter Democrats purport to be interested in when the country at issue is Russia and the bottom line helps them politically.

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More to the point, though, while Schiff claims that Biden corruption and Ukrainian election meddling have no relevance to the inquiry, he is not conducting the hearings that way. To the contrary, Democrats are raising these matters at will … with witnesses of their choosing, who have no relevant information.

Democrats then use the witnesses’ professions that they’ve heard nothing of Biden corruption or Ukrainian collusion as if it were evidence that these things did not happen.

In a legitimate proceeding, you can’t have it both ways.

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Schiff is plainly hiding the ball when he claims the defense the president and Republicans want to pursue is irrelevant, but then asks safe (i.e., uninformed) witnesses about this defense in order to pretend that there is no evidence.

The chairman’s own conduct shows that the Bidens and the 2016 shenanigans of Ukrainian officials are germane to the inquiry and would be probative of why President Trump wanted Ukraine to investigate. If the inquiry is to be something other than a political stunt masquerading as serious impeachment business, Republicans must be permitted to present their side of the story.

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