Third, an obstruction case is difficult when the prosecution is dealing with damaged witnesses—that is, witnesses who have previously been convicted of lying (some even after pleading guilty) or who are likely to lie to defend Trump out of loyalty to him. Who are some of the other people who might be able to testify to Trump’s intent? Paul Manafort? Michael Flynn? Both are suspect because of their prior criminal pleas (and, in Manafort’s case, his postplea conduct). How about Donald Trump Jr. or Jared Kushner? Good luck getting truthful testimony from them. It’s hard getting children to testify against parents generally. It will be doubly hard in the context of this highly charged (and, in their view, politicized) context.
Fourth, and finally, many of the president’s actions took place (as Barr notes) in public view. This is not, of course, determinative, but again it does tend to negate intent, since the obvious response is, “If I thought it was obstruction, would I have done it on television?” Of course, a cagey criminal could game the system by obstructing in public, knowing that it weakens the prosecutor’s factual case. But the burden of proof lies with the prosecutor—and so that caginess is just a realistic assessment of how difficult proof beyond a reasonable doubt is or can be in contested cases. Here, as I said once before, it is likely that the president’s best defense to an obstruction charge is that he is ignorant of the law and of his role in the government.