I don't want to preempt what Robert Mueller has found or what he is likely to find from the testimony of Michael Flynn but I suspect that Mueller probably knew what he was looking for before Flynn was ever brought in to be questioned, and the as yet unnamed but "very senior" member of the Trump transition team who has been pointed at, has the surname of Trump. Exactly what Mr Mueller will find with regards to collusion and interference into the 2016 Presidential Election by the Russians, I also have no idea but I am willing to suggest that however bad it may look, it will still not be enough to impeach the current occupant in the Oval Office chair.
The specific conditions contained in the US Constitution which outline the impeachment of a President say:
The President, Vice President and all civil officers of the United States, shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors.
- Article 2, Section 4, US Constitution (1789)
The thing about an impeachment case is that the Congress needs to specifically pin the causes for impeachment on the President himself; not his advisers and staff, however close to him they might be. At the moment, I would suggest that that is impossible but given the absolute horrorshow of the current administration, I think that the chances of something being pinned on him eventually, will asymptotically rise towards 100%.
Given that I think that the chances of President Trump having done something which warrants his impeachment is likely, I'd still put the absolute earliest date at this taking place as March 4th, 2019.
As it currently stands, the Republican party controls all three rings of the circus that is the US government. They control both houses of Congress, they control the Presidency, and they nominally control the Supreme Court. The power to impeach the President lies with the Congress and while Republicans control both houses, the chances of them pulling the trigger on one of their own, however strained the relationship between Donald Trump and establishment Republicans may be, is zero.
That means that there needs to be a definite and distinct change in the composition of the Congress and given the failure of the Republican Party to as yet pass any piece of meaningful legislation, the anger directed at the President for everything that he's said and done, and the impending taxation reforms which will simultaneously benefit the rich and cripple future budgets, I think that that change will be great. There is usually a swing in the pendulum against the President in the first mid-term election after their election but I suspect that on this occasion, the pendulum will really be swinging against the President and Republicans in the Congress.
If that's true, then the earliest that impeachment proceedings would begin would be the first week in January 2019 and because I think that the weight of evidence against the President will be great, due to massive incompetence by the administration to even so much as cover their tracks, then the formal proceedings would only conclude after it has passed through a committee stage. That would most likely take about a month and then there would be the formal impeachment proceedings in Congress, which would also take some time; which is why I give the date of March 4th, 2019 at the earliest.
Of course this is contingent on the Democrats taking back the Congress and given people's predilection to vote against their own interests because they still want to vote for their team (voters are mostly irrational actors), then the whole process would be short circuited and that would push the impeachment timetable out to 2021 and after the members have arrived from the 2020 election. The problem there is that that assumes that Donald Trump would be re elected in 2020 and I just don't think that that's likely. It could very well be that the conditions which would be necessary to impeach Donald Trump, only exist after he has been elected out of office; which makes this whole speculation moot.
It is noteworthy that there hasn't been a successful impeachment of a President. Andrew Johnson avoided it when the Senate decided against it, despite the House being in favour. Warren G. Harding who should have been impeached, died before that could happen. Nixon resigned before he was impeached and then given a pardon by his successor Gerald Ford because that would have made his own presidency virtually impossible to administer with that still hanging around. Clinton should have been impeached but was seemingly made of Teflon and so nothing stuck to him.
If Trump isn't impeached, it won't be because he's some kind of mastermind because that would assume that there's been some grand design to be masterminded and clearly the whole Trump administration has been unminded since before its inception. I think that Donald Trump's plan for the presidency extended as far as November 8th, 2016 and no further.
If there were to be impeachment charges drawn up against Trump, I think that the most likely centre around obstruction of justice and his attempts to fiddle with the FBI. Again, that will centre on whether or not Mueller finds any smoking guns before the whole White House burns down.