A number of Republican Senators state that the trial is unconstitutional as Trump is no longer in office.
I reviewed the text of the Constitution regarding impeachment, and this line in bold stands out indicating this trial would be constitutional:
"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.
Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law."
Do these GOP Senators that are trying to avoid the trial on procedural grounds have a basis when the trial can serve the purpose for the disqualification from holding office. The House sent the impeachment articles when Trump was still in office, so once the Senate led by Schumer tries it, I don't know how the GOP Senators can still stay it's unconstitutional.
Very simple answer. For bring the party that likes to bang the old “but the constitution says...!” drum, most of them have almost certainly never actually read the document. Likely the same for both parties.
The constitution I fear is going to slowly turn into the Bible. Certain parts are meant to be taken literally, and others you must interpret...depending on which view is more beneficial at any given moment.
I firmly believe the way the Declaration and especially the Constitution have been elevated to sacred text status will lead to considerable problems in the future. It was never intended to last this long in its original form, and perpetual renewal for modernization was always the hope. Just imagine Congress trying to ratify an amendment these days. You could try to pass an amendment that just says “terrorism is bad” and it would likely stall in the senate while they argue over the definitions of terrorism, is, and bad.