Should a 2LT salute a 1LT?

This seems like an easy question to me. Yes, the junior person salutes the senior person.

Is this really a question? Salute and move out.

B. Answers it to a "Tee!" Regulations are not up for debate! Like our laws, if you don't like them work to get them changed! Until then, if you wear the uniform do the right thing or pay the consequences if it comes back to haunt you! Ha! - Top

There is no question about it. Any junior member of the armed forces salutes any officer higher in rank than themselves and this is not service specific, but applies service wide. This was a "bone of contention" when I went to USMC RWOBC at Camp Barrett at MCB Quantico back in 79 with 18 enlisted years behind me. The Prior-Service Staff Sergeants and Gunnies had no problem with this regulation, but the much younger NCOs Cpls and Sgts felt the need to be seen as "Salty" (Term we used to refer to seasoned veteran members of the Naval services) and used to say " I'm not saluting some "Butter Bar" who doesn't have as much time in the Corps as i have in the chow line." Or "I have used more ink signing paychecks than those "Butter Bars" have drunk coffee." Well the former Staff and Gunnery Sergeants had to fall back on their enlisted training and "Hold Court" with the younger generation.
You always respect the rank and that is what you traditionally salute. If you don't, then when you wear that rank you will not have a reason to expect it to be respected by others.
While you are right that the person wearing the rank has the responsibility to earn respect, they do not have to earn the right to be saluted. If they are a Commander, who leads by virtue of Authority or a Leader who Commands by virtue of Respect, that fact will be clearly evident in their attitude and behavior and the performance of their unit will be correspondingly displayed.

Of course the 1LT deserves a salute - more if he is in a position as the commander, EXO, within the unit. However, we should all "earn" the respect of the salute from our enlisted and NCOs (which is a right of passage).

Military courtesy as well as common courtesy, if the person outranks you ....render a proper salute.

As you stated AR 600-25 covers this question. A 2Lt is junior to a 1Lt so should salute. Is a SFC senior to a SSG? After all they are both addressed as Sargeant. Is a LTC junior to a COL.? They are both addressed as COL. Get my meaning? Junior is junior period.

Not a good question to ask any Marine. JR ALWAYS salutes SR. Master Gunny can not believe you are even asking this question. Covered in basic training...Semper Fi

This is a stupid question. It would be the same as asking should a Lt Col. salute a Colonel? Should a 1 star General salute a 2 star General? The answer is plain and simple, hell yes!

Even though I have liked only a few LT's over the years. I thought this went without saying.