It happened before
It has been reported by our media that (on an earlier state flight) the Polish President himself has ordered the PIC to start an approach into an airport that was basically closed.
It's not only possible, but well documented fact, mentioned here before.
The President ordered PIC to land in a war zone near Tibilisi, although the
flight plan was for another safe destination.
The PIC refused, was later, after returning attacked by the President
for insubordination and pressure was made on the military to fire him.
Instead, the Minister of Defence rewarded the pilot with a medal (silver)
for bravery and maintaining his integrity and standard in face of unusual situation.