If every president (or other leader, this isn’t just about the USA) genuinely needs the power to do certain things which are against the constitution of their nation, the correct solution is to change the constitution to reflect reality.
If a government allows its employees to get away with doing things which are against that government’s own rules for their own operation, then a few bad apples spoil the whole barrel.
If you need government spies secretly looking on certain citizens without the targets being aware of it via a warrant, make sure they can’t ever be used like Nixon. If you need government assassins, you definitely don’t want them used the way Nixon used government spies.
If a government allows its employees to get away with doing things which are against that government’s own rules for their own operation, then a few bad apples spoil the whole barrel.
If you need government spies secretly looking on certain citizens without the targets being aware of it via a warrant, make sure they can’t ever be used like Nixon. If you need government assassins, you definitely don’t want them used the way Nixon used government spies.