A manager who protects his employees from higher managers, or one who shows his employees mistakes to higher manager to protect himself. Who's better?

Well, it's a combination of both. As a manager, you cannot simply keep hiding every mistake of your subordinate from the management for ever. Ultimately it will tell on your own results, and you (and the others) will need to work that much harder to cover the ground which this poor employee leaves.

But at the same time, one should not expose every mistake upwards - it kind of shows that the manager does not have the moral courage to own up for the mistake of his subordinate. One can only delegate authority, not responsibility. Therefore, even when you have delegated, the results of a mistake will rest on your table only.

Therefore, if a person keeps repeating the same mistake again and again - whether through negligence / arrogance / don't care attitude, one will have no option but to expose him. But if the mistake is a "honest" one, a "genuine" one, then he will need to be supported.

It depends on the conditions, if the mistake is recoverable and harmless for the constitution, then the better manager is one who didn't highlight it in front of others, but if that faith is becoming to be a movement of any harm to the company than it should be spotlighted.

The person who protects his employees from higher management is always better.

But need to sure on what aspects he / she is protecting them. If the employee is involved in any unacceptable activity as per the companies policies, then protecting them will always lead us in trouble.

But in case if the employee had committed any mistake unknowingly which can be rectified then protecting them makes sense. 

Well, it's a combination of both. As a manager, you cannot simply keep hiding every mistake of your subordinate from the management for ever. Ultimately it will tell on your own results, and you (and the others) will need to work that much harder to cover the ground which this poor employee leaves.

Mistakes helps to climb the ladder.  No man is perfect. But at the same time, one should not expose every mistake upwards - it kind of shows that the manager does not have the moral courage to own up for the mistake of his subordinate.

Therefore, if a person keeps repeating the same mistake again and again - whether through negligence / arrogance / don't care attitude, one will have no option but to expose him.