Should a 2LT salute a 1LT?

The salute is acknowledgement for the position of rank regardless of experience of training, and or time in the service, you may not like the individual, but it goes back to professionalism of the services and respect. I may not have agreed in the past with some of my officers, however they were my superior, and they earned that salute by completing training required to lead young men and women that I had not. This maintenance of military protocol and professionalism saluting a superior officer not only demonstrates the junior officer's or enlisted person's professional behavior, it exemplifies the dignity and heart of a true warrior.

Yes he is junior

I've ben both, and the age old saying, there is no rank among LTs was the thing back in the day. Now if a 2LT is reporting to a 1LT as a CDR, that's different.

NO

Yes- they are superior to them

Of course! Wondering why this is even a question.

No

Over in Germany back in the Cold War days we had a group of young Lts that habitually took a shortcut from their Apaches to the O-Club at the end of the duty day. They cut right through the an outdoor maintenance area where quite a few of their aircraft mechanics were getting ready to roll over and service their choppers.
They seemed to be quite engrossed in their conversations and tended to ignore the young army troops working along their path as they rendered salutes and greeted the intrepid flying warriors.
As the Rod and Gun Club RO, a lot of the young troops knew me and over a few beers told me how worthless and weak the attitude of those young officers made them feel.
I arranged my schedule to be in the area in question a few days later at the end of the duty day, observed the same young officers exhibiting the same disregard for the honors being rendered and stepped in.
"Gentlemen," I said addressing the gaggle of aviators, "I would like to have a word with you" Apparently my command voice tone was enough to interrupt their concentration and get their attention.
The group turned and I executed a sharp salute, held it for a few seconds, and dropped my hand.
Some of them returned the salute instinctively and others sort of looked shocked as their arms moved without thought but not completing the motion.
"I've heard rumors that a group of officers has been reluctant to return salutes to the enlisted folk working in this area" I announced, "That wouldn't be you, gentlemen, would it?"
FWIW I was in a NATO issue sage green coat, wearing a grey bunny hat, unbloused green fatigues and no insignia. The correct uniform for my service and assignment there.
After getting no clue to whom they were speaking from my completely blank clothing a couple of officers started to protest my interrupting their stroll.
"Gentlemen, we can discuss this among ourselves here or in the CSM's office. I see his light is on and know he's working late tonight" I said, pointing to the appropriate window glowing one building over.
The group settled down and listened while I gave a brief history of The Salute, quoted a couple of lines I'd lifted from the Army regulations that afternoon, and closed with the hopes that in the future we wouldn't have another conversation of this sort.
After another salute that was returned with enthusiasm, I performed an about-face and went back to my own duties...
In all that I was respectful, assisting them with my experience as an NCO, and trying to solve the problem at the lowest possible level. I never told anyone what I'd done, it was just a problem that I, as an NCO, was asked to look into and I felt it was taken care of...
The kids that had complained to me were amazed that they started getting their salutes returned. Hopefully, that helped them feel more like valued members of the team, after all, THEY worked through the night keeping those helicopters fixed and flying, while the young Lts who just drove them entertained themselves in the O-Club<G>

Don't understand this discussion. Rates should always salute officers. Warrant officers included. Junior officers should always salute senior officers. 2LTs are junior to 1LTs. LCs are junior to Col. I just don't understand these questions. Maybe you were asleep in basic?

Nope, both LTs.