Here's what the constitution says about impeachment:
The House of Representatives shall chose their Speaker and other Officers; and shall have the sole Power of Impeachment.
The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside. And no Person shall be convicted without the Concurrence of two thirds of the Members present.
there is no mention about having to submit an impeachment to the senate
if house managers refuse to prosecute the case, that's tantamount to summary judgement
regardless of what lawrence tribe might claim it doesn't seem nancy has any control as to the timing of when the senate might take up an impeachment
if there is a duly voted and passed impeachment by the house of representatives, in accordance with house rules, there is an impeachment
as regards impeachment the house of representatives has one of two options, impeach or not impeach.
once impeached, the senate takes over.
if an impeachment is somehow not able to be considered by the senate, the only cause would be that there was no impeachment
doesn't seem that pelosi can have to both ways