In regards to members of the Senate and/or House of Representatives not attending the inauguration, here’s a reminder of the oath you took when you were elected:
I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter: So help me God.
This doesn’t say it’s OK to disrespect the highest office held in the United States of America just because you don’t like who was elected. I didn’t vote for Barack Obama, and yet I still acknowledged him as president. I listened to most of his speeches — not all but at least I admit it — and there were a lot of things he did that I disagreed with. But let me make myself clear: Donald Trump is (at the time this letter was written) our president-elect. If you’re not happy about it, then resign your office immediately, because this is not only an act of childishness, but it is also disrespectful to the office to which you were elected.
Charlotte Kilzer, Cahokia