Just under the deadline, Republicans turned in on Saturday the list of witnesses they’d like to have testify at impeachment hearings beginning this week. Among them is Hunter Biden, former vice president Joe Biden’s son, who Trump wanted Ukrainian President Volodymyr Zelensky to investigate as a condition of getting U.S. military aid. In listing Biden as a witness, the GOP may hope to build a defense that shifts the focus to alleged wrongdoing by the former vice president rather than by Trump. But what Trump alleges against Biden is exactly what he is being accused of himself — which makes any defense of his actions focused on the Bidens internally inconsistent, and ultimately just helps make the case for impeachment.

At the heart of the current scandal is Trump’s insistence that Zelensky make a public announcement that Ukraine would investigate actions by Biden when he was vice president. According to Trump, Biden demanded that Ukraine fire its then-prosecutor general, Viktor Shokin, to stymie an investigation Shokin was conducting into a company, Burisma Group, for which Hunter Biden served as a board member at the time.

There is no evidence to substantiate these allegations. Ukrainian officials, in fact, have stated that they have found no evidence of wrongdoing by either Biden. But let’s assume, for the sake of argument, that the allegations have merit. The thrust of Trump’s claims is that Biden’s actions were corrupt because he undertook an action in his official capacity to receive a personal benefit (via his son). This is exactly the claim against Trump with regard to his actions with Zelensky — and therein lies the trouble for his defense.

The idea behind bringing Hunter Biden into the impeachment inquiry is to create a “good faith” defense for Trump. Republicans hope to show that Trump had a reasonable basis to be concerned about Joe Biden’s actions, and that he had legitimate grounds for wanting Zelensky to look into Biden’s alleged corruption. The idea there would be that as long as Trump was acting even in part in the public interest (that is, “fighting corruption”), then any personal benefit that he might receive as a result — say, in the form of election assistance because of a public smear on his potential opponent — is ancillary and irrelevant.

The problem is that Trump’s basic premise undercuts his defense: The “good faith” standard Trump hopes to argue would apply equally to Joe Biden. After all, in calling for Shokin to be fired, Biden was also acting in his official capacity as vice president and carrying out the foreign policy directives of the Obama administration to encourage Ukraine to fight corruption — something that the European Union had already been calling for and welcomed when Ukraine followed through. Biden’s “good faith” is even more evident than Trump’s, since he conducted his actions publicly, through official channels, and in conjunction with international partners. By Trump’s own argument, all of these factors would negate any self-serving benefit to the Bidens that came as a result. In other words, the “good faith” defense concedes that Trump had no reason to ever call for an investigation into the Bidens in the first place.

Conversely, attempting to litigate the Biden issue only underscores why Trump’s impeachment hearings are warranted. In calling Hunter Biden to testify, Republicans ostensibly hope to show that he benefited from his father’s actions, which theoretically quashed an investigation that could have hurt him. The implication would be that Joe Biden’s motives mattered: If his official actions were driven by a personal interest in helping his son, that would be corrupt and worthy of further investigation, and even criminal prosecution. Again, since Trump is similarly situated, such an argument would demonstrate precisely why using his leverage over Ukraine to publicly smear a political opponent — which would benefit his 2020 election campaign — would be an impeachable, and potentially criminal, act.

Republicans are desperate to find any defense at all on which to hang their hats, so the incoherence of their approach in focusing on the Bidens is unsurprising. With no better options — particularly as more damning evidence comes to light each day — they may just be hoping to confuse the issue and provide fodder for voters to conclude that everyone is corrupt and that therefore Trump’s problematic actions don’t matter. They know that “but her emails” succeeded in displacing attention from Trump’s many misdeeds in 2016, and attempting a new version of it in 2020 might look like their best bet to hold the White House.

If so, they may be underestimating the difference between an impeachment proceeding and a campaign. With support for impeachment growing, especially among independents, voters may be more likely to approach the impeachment hearings and trial as jurors do a court proceeding: Looking at the evidence presented and the logic of the legal arguments made for and against the president. Although they do not have a direct say in whether to remove Trump, their waning support for the president may matter to the senators who do. Republicans also underestimate the ability of skilled litigators — like Barry Berke, an attorney for the House Democrats — to quickly dismantle disingenuous legal arguments (Democrats and Republicans will each have 45 minutes of uninterrupted questioning for each witness, under the current rules established by the House). By trying to distract from the substance of Trump’s actions, Trump’s latest defense may well make the case against him.

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