The House impeaches, the Senate convicts or acquits, by a 2/3 majority.
Impeachment, in and of itself, is not useful. The trial in the Senate is.
What the Democrats have committed to, IMO, is making sure that impeachment is used for a just cause - not like the Republicans used it as part of their clown show pageantry with Bill Clinton.
The miscalculation by Pelosi and those who agree with her is, simply, that Republicans are traitors and their base lives in an alternate reality altogether. Why try to convict one of yours if you can make it look like the other side is just playing politics? They have lied and gaslighted their way throughout, successfully railroading their agenda through without any real accountability. There will be no bipartisan agreement to hold Drumpf accountable, because they would have to admit they've been complicit all along. That's not going to happen.