It is certainly possible that the Mueller Report to be released on Thursday will constitute a blueprint for impeaching President Trump on obstruction of justice charges. My speculation is based mostly on the aggressiveness with which the lawyers on the Mueller team did their investigation and their keeping the Russia-Trump investigation open long after they had to know there was no collusion between the Trump campaign and Russia.

Andrew McCarthy has been particularly insightful on what was happening:

The collusion probe came to Mueller primarily as an obstruction case. Since it was obvious from a very early point that there had been no collusion, the question of whether there was a prosecutable obstruction case was really the only one Mueller had to answer. In the end, he defaulted. It is almost certain that Mueller knew by autumn 2017 that there was no Trump–Russia conspiracy. Trump railed about the investigation for public consumption, but the White House and his lawyers (especially the first team, led by John Dowd) provided sweeping cooperation, including hours of interviews with White House counsel Don McGahn and well over a million documents (among them, contemporaneous notes of McGahn's meetings with the president). Though he could easily have claimed executive privilege to withhold this information from prosecutors, Trump never did. . . . A nagging question persists: Why did Mueller allow the investigation to continue for well over a year after it must have been patent that there was no collusion case? . . . Why did neither Mueller nor Rosenstein issue an interim report? That would have enabled Trump to govern without a cloud of suspicion that he might be a clandestine agent of Russia, yet permitted the overarching inquiry into Russia's operations and even the obstruction probe to continue. The country deserves an answer.

McCarthy gives some background about the likely reason that Mueller failed to decide whether to prosecute, ultimately punting the decision to Barr:

As for the obstruction inquiry, after 22 months of investigation, Mueller finally declined to make a prosecutorial judgment, dumping the matter in Barr's lap. . . . There is no doubt that a president may be cited for obstruction based on corrupt acts that tamper with witnesses and evidence (recall the Clinton and Nixon precedents). But no patently illegal acts were alleged against Trump. In their absence, Mueller's team pursued a novel theory: An obstruction charge might be premised on lawful exercises of the president's Article II prerogatives (e.g., firing subordinate officials, weighing in on the merits of investigations, considering pardons) if a prosecutor — the president's subordinate — later deduced that the acts had been improperly motivated. . . . As is not uncommon for former top officials, [Barr] had weighed in on important policy matters from time to time over the years. So it was on obstruction. In June 2018, Barr had submitted an unsolicited 20-page memo to Rosenstein. Citing the legislative history of the obstruction statutes, leading case law, and longstanding Justice Department policy, he contended that Mueller's apparent theory of obstruction was legally untenable and practically unworkable. Putting the president aside, the theory would subject to possible prosecution any Justice Department supervisor who made a routine personnel decision during a case (say, reassigning a lawyer from one investigation to another) if some prosecutor later suspected an improper motive. Barr further made what should be an incontestable point: Given the damage such a prosecution can do to the nation's governance, a president should not be prosecuted in the absence of something all reasonable people can agree is a clear, serious violation of law. Once Barr was confirmed, Mueller had to see the handwriting on the wall: The new AG was not going to approve a dubious obstruction charge. The special counsel thus had a choice: concede that Barr was right on the law, or fight for the controversial theory his staff had pursued — i.e., recommend an obstruction charge and dare the AG to nix it. But Mueller shrank from making the decision, choosing merely to summarize the evidence and leave the prosecutorial judgment to Barr. In consultation with Rosenstein, Barr found no prosecutable case. . . . In the meantime, [Mueller] let the president chafe under the yoke of suspicion long after it was manifest that there was no collusion case. All the while, the special counsel's staff considered an unsound reinterpretation of obstruction law in order to nail Trump — after the Justice Department had bent over backwards in order to avoid charging Hillary Clinton with mishandling classified information, a concrete criminal allegation that was supported by weighty evidence.

Although political predictions are wrong nearly as often as they are right, I would expect that the Mueller Report released on Thursday will give plenty of ammunition for Congressional Democrats who might want to impeach Trump for obstruction under a theory that the Mueller team thought plausible enough to have spent nearly two years pursuing.

I hope that the report will also reveal when the investigation of the Trump campaign began and on what basis, as well as which current and former foreign agents or governments were used by the Clinton campaign, the FBI, or the CIA to surveil or gather information on members of the Trump campaign, the transition team, or the administration.

UPDATE (April 18, 1:12pm ET):

Now that the report is out, some other commentators (such as David Axelrod) bear out my prediction: