I'm not clear on her motives either. Is she trying to extend the period that the President is smeared before he is acquitted? Is she literally not going to submit the matter to the Senate for trial? An attempt to forestall acquittal altogether? Would the House majority stand for that? Whatever it is, its dirty. If I was the President I would hammer the House by every means available. Denial of military aircraft and vehicles. Conduct the State of the Union Address from the Oval Office. Veto all legislation and govern by decree. Sue House leadership for obstruction and libel. Refuse to meet with Pelosi and Schumer on anything. Stop cooperating on Oversight. Whatever hurts them. Let everything go before SCOTUS, absolutely everything.
Even for as much as a leftwing wacko as Nancy is, she is still a politician who knows how the game is played. She has a bunch of fringe lunatics who she cannot control who pushed impeachment and she had to hold her nose and go along. Now she is stuck with an unpopular impeachment and is looking for a Hail Mary. She could hold the impeachment from the Senate or give it to the Senate and let them acquit. Either way, she is hosed. She is going to look even worst if Trump is re-elected. If that occurs she will go down in history as the Speaker of the House who impeached a President, and then that President went on to get re-elected less than 11 months later. That will not be a good look and will be the end of Nancy Pelosi, Adam Schiff, and Nadler.
Well it is the holidays, perhaps she is just waiting for the session to resume in January to present them for full effect.
The short version is that she has lost control of the process and is looking for a way to get out but at least show that she inflicted serious damage on to Trump. Pelosi never wanted this impeachment and desperately tried to head it off, but the lefties and the power and attention seekers running their own agendas (Nadler and Schiff) outmaneuvered her. Eventually she caved in because the polls were strong enough in favor of impeaching that she felt that she could at least pull it off and benefit from appeasing those who wanted the impeachment- although still being opposed to it herself, knowing the messiness of it and that it would benefit Trump. Problem is the polls shifted, making it an even worse trade to take, risk to reward-wise. So then she though that Bolton and Mulvaney could be her savings grace -ie, if you could get the in before the Senate trial then they would inflict enough damage on to Trump for her to be able to say that she impeached Trump and blew both of his legs off at the trial even though he was acquitted. But then Mitch announced that they would not be having any more witnesses at the trial. The House investigated at length and had witnesses up the ying yang and now the Senate would just be making a judgement upon the existing set of facts. Translation: No Bolton or Mulvaney bombshells allowed and if you go to the Senate you just go there to take it up the bo-bo and then it is over. Not want Nancy needs to get out of this mess. So, that's a long winded way of getting to what she wants out of this: She wants to extract an agreement from the Senate that they will allow new witnesses in return for her sending the charges over to the Senate. It's a disaster. She thinks that she has a fine-tuning knob on a train wreck- but it does not work that way. What does her threat consist of? Oh, I see. "Allow Mulvaney and Bolton to testify of I will refuse to impeach the president." Not the zippiest strategy. It is probably too much to replay right now, but keep in mind too, that even if Mitch agreed to allow those witnesses to be called that Trump may block it by asserting Executive Privilege for their testimony, which would then spin it off in to the courts and whatever timetable that requires. The lefties will argue that Executive Privilege may not be allowed in an impeachment trial because impeachment has its own source of authority in the Constitution. It will still take lots of court time to conclude that even if one were to accept that argument, which I don't. But that's what she wants. She wants to be able to damage him even further if she cannot win. Right now if it goes over to the Senate all they are going to do is rehash what the House did and watch the dems bend over and take it. That is not a good look for her or the party. Take home message for Nancy: No fine-tuning knob on a trainwreck.
There was, I think, some forlorn hope that the work of the people would be a higher interest than Orange Man Bad. Pelosi is a partisan politician, not a legislator. Many knew this from the way Obamacare was rammed through in the middle of the night but its taken some more shenanigans to convince everyone. Now its clear. Democrats want to harm the President so its time to harm them by every legal means.