We don’t know that, and it’s the right thing to do regardless. It’s just a weeklong trial, it’s not unduly burdensome. The taxpayer dollars argument is pretty weak sauce. It’s just something people throw at the wall whenever they can’t think of a real reason to oppose something the government does.
From a pure political perspective, Democrats can’t wait to get Republicans on record supporting treason.
Yeah impeachment is partisan. The GOP made sure of that the last time and this time too. That said, this will be the most bipartisan impeachment in history.