It's common sense that the highest political minister of a nation shouldn't accompany with his most prior succesors such as deputies in any journey with any risk
Keep in mind
Tolkien wrote his
Middle-earth to be very similar to Feudal and early Middle-age times.
In those days, it was common for the "feudal King" or early Monarch to lead their people into battle.
The relationship they held with one another was very different than what has been seen from the late Middle-ages to beyond.
Support of the leader was because of love, not command or requirement. If people didn't like their relationship to the King, they simply moved and chose another.
The
Kings supported their own
armies... there was no excess taxation on the
peoples to fund and support them.
So 'common sense' of today simply does not apply to what would have been done in Tolkien's Middle-earth.
It was only after centralization of power, increased taxation to fund everything on the backs of the now totally unknown people, etc. the leaders started using others to fight their
battles for them while they stayed home safe and sound.
(I won't take this line of reasoning any further here, as it's really a tragic bit of history to lose, and has been widely perverted by the 'winners' who managed to bring the early middle
ages to an end, other than to say there's a great difference after Rome, during the years roughly 800 - 1300 in history, and from about late 1300s on into the 'Rennaisance' which is rightly named, meaning "a return'' - i.e. 'bringing back all the Roman centralization, taxation and corruption.)
To understand Tolkien's Middle-earth is to understand the period he most favored in terms of his political perspectives. A good deal of work needs to be done, and what we now feel to be 'common sense' for a number of reasons, left behind.