Jon Sopel's analysis is very pertinent (Jon is the BBC's North American editor):
And so it is done. Donald Trump now becomes the third member of the exclusive club that no-one wants to be a member of.
But the framers of the constitution with its impeachment provision could never have imagined the hyper-partisanship - on both sides - that has been witnessed during today's sterile House proceedings. Each side with its own narrative, neither side listening to the other. And one can say with some certainty - I would bet all my yet-to-be-gifted Christmas presents - that it will be much the same once this becomes a trial in the Senate in the New Year.
Donald Trump will be acquitted. He won't be forced from office. So what changes? Well, Donald Trump will have a place in the history books - and for a man with such a huge sense of self that will hurt. Acutely. But 2020? Far from this being a killer blow against President Trump, it might turbo charge his bid for a second term. The House Speaker Nancy Pelosi was always wary about going down the impeachment route. We'll discover next November whether that concern was well founded.
It would appear the American justice system has been taken over and ruled by partisan politics. Only yesterday, Lady Hale, the UK's head Supreme Court judge, warned Boris Johnson not to follow suit.