I agree with you that what is happening here, on both sides of the aisle is constitutional. If the House impeaches and the Senate declines to convict, then that must be the way it goes. The constitutional requirements are met, and there's nothing more to say.
I'm also beginning to wonder if it might not actually be better for the House to vote against impeachment (that would require a few dozen Democrats to not toe the party line). I mean, there have definitely been shenanigans on the part of Trump and some of his supporters (Giuliani, for instance), I'm beginning to suspect that this might actually be a pretty weak case. And if that's so, it might be better to shelve the entire thing. The Democrats could easily say, "we saw a duty to investigate, we did so, and we found some things that were dubious, but the majority decided in the end that it wasn't enough to warrant a very disunifying impeachment."
And then everybody could get on with the business of telling Americans why they should be elected in 2020 (rather than harping on why the other guy shouldn't).
I agree with you. However, the democrats promised the radical part of their base an impeachment, and once they began, they had to calculate where the least harm to their political goals would be.
They calculated that angering their vocal very left leaning members would do more harm than following through on impeachment. They can say to these people, we ted to nail him to the wall, but the mean old Republicans let him off.
They never figured that their tactics and the weakness of their case on national TV would harm them with Independents, those who really elect the president. They were bewildered by the fact that after each of their hearings of the show trial, they lost more support in this demographic.They though they had choreographed everything well enough to damage Trump.
Further, the 31 democrat house members elected in Trump districts are terrified they will face retribution for impeachment.
So, they satisfied their radicals, but alienated others.
They could have gotten bipartisan support for censure, and for a short while that seemed the way out. A poll of their radicals showed them that this wads unacceptable. So they had to be all in.
I think time will prove this to have been a giant error on the part of the democrats. The Republicans paid a big price at the polls for impeaching Clinton, and he actually committed a crime, perjury, and had his law license taken away from him.
We will see.