For weeks now, amid a bitter tactical struggle between the leaders of the House and the Senate, there has been great uncertainty about how the trial of President Trump would play out.
It wasn’t clear when the Senate would begin its work or how much peril the President was really in.
Would Republicans simply dismiss the Articles of Impeachment and let Donald Trump off the hook?
Well, we now have some light shining on the process - but also one remaining mystery.
- Robert Moore explains what happened on Wednesday and what to expect over the next few days
The timetable is finally clear.
On Thursday afternoon the Chief Justice will be sworn in.
Two hours later, the 100 US Senators will take their special oath.
The ceremonial part of this will be wrapped up by the end of Thursday.
Then there will be a further four day pause while all Americans - including Senators - enjoy a long holiday weekend.
But on Tuesday, it’s game day.
The trial of Donald Trump will get properly underway.
The House “managers” - in effect, the prosecutors - will present their case to the Senate.
They will argue that the President committed “high crimes and misdemeanours” and should be removed from office.
Then the President’s lawyers will respond.
All of that should take about a week.
But here’s the remaining mystery: will Republicans allow fresh witnesses and new evidence to be introduced?
If so, we may hear from key players who could have damning evidence against the President.
Much of the focus has been on testimony from John Bolton, Trump’s former national security adviser.
What secrets does he possess?
But other shadowy characters linked to the Ukraine scandal are also emerging out of the woodwork.
In other words, this could become a real trial, with all the unpredictability of new witnesses.
The White House wants the trial to be over as soon as possible.
Originally, Trump viewed the prospect of drawn-out proceedings to be a “win” for him.
He thought it would show Democrats to be petty and vindictive, and would generate fresh anger and energy among his supporters.
But that may have changed.
The White House is worried again.
The President’s advisers know that Americans are watching closely and that one false move could undermine Republican unity.
So the outcome of this trial is not a foregone conclusion.
Yes, it seems inconceivable that 20 Republican senators will defect and vote for the President’s conviction and removal from office.
But this is America in the era of Trump.
Crazier things have happened.