A lesson I learned to late but is worth knowing if you truly want to have an impact.

I observed interesting things about the military while working on my Dissertation. I noticed those with the greatest talent would find themselves in demanding positions (sometimes they were lucky to find a mentor, who repaid their hard work by underwriting mistakes), other hid their true potential or left the Army. The hard worker with top cover from a mentor was usually the most successful and it is why most O5s and above advocate finding a mentor. I was hard headed early in my career but with observation and numerous senior officers coaching me to develop the habit of making my boss’s problem my own. I had some great leaders toward the end of my Active Service that would underwrite my mistakes. The secret to gain this kind of mentorship was finding out what the senior officer thought was important but did not have time to do themselves and championing their cause or managing their project. There is a lot more to this but anything more would be confusing. Instead, what I will use is a metaphor to explain the difference between brown nosing and subordinating your focus and goals to those of senior rank and position. While honey gets more flies it is a sticky mess without an object to put it on. That object is work which is the substance that gives real value over the long term. Now the value of that work depends on the perspective; so the best work, in addition to what you do normally, is that which already has value to those who’s opinion carries weight. An additional skill to develop is the ability to anticipate what your boss wants. This skill is developed through listening and observation of the boss’s goals, once you have developed an understanding, you develop a relationship qualified by trust and mutual understanding.

Disclaimer: Not everyone will agree with you, not everyone will agree with you boss or mentor, your next boss may not agree with your last boss, sometimes you will find resistance from those trying to undermine your boss.

Disagreement is not disloyalty.
However, undermining a senior leader for the sake of one's ego, laziness, ignorance, stupidity and just toxic disposition to others is disloyal and insubordinate.
Another underhanded way is to be disrespectful is to turn and breif others something to the effect of "I know this is crazy but you know the boss, we are doing this because he or she told me too" This is failing to take ownership and is weak, it tells the audience that heres it you do not take it serious and do not take your boss serious therefore everything you say is suspect and does not have to be followed.

You can be a Toxic Subordinate, if you can be a Toxic Subordinate, you could therefore be a Toxic Leader.

The military has a hiearchy, take ownship of our commander's intent and accomplish it.