If Trump is removed from office for breaking the law, the judge and jury would be Americas' senators. That's constitutional and that's the way the Democracy works.
Yes, the Senators decide and since the majority are Republicans, Nip can't complain that they would vote to convict unless there were serious criminal charges.
I do wonder what happens if there is a tie. Does the V.P get a vote in a situation like this? Typically yes, but here it would be a conflict of interest.
But while I don't want Pence as President, it would be funny to see Pence break a tie by voting to convict Trump!