That's actually one of the reasons the president has a veto. If the president doesn't want the law to pass, then there isn't much point in passing it unless Congress makes a show of force with the 2/3rds majority, which is also the majority needed to remove him from office.
Similarly, one of the reasons the president has a pardon power is because he doesn't have to enforce those federal offenses. E.g. imagine that a president without pardon power instead offers "plea deals"/settlements for a $1 fine or concocts vacuously lenient house arrest enforcement.
The original constitution basically accepts that there is very little you can make a president do, and it instead formalizes what would otherwise be a gray area (it does have plenty about what he can't do). Some of this has changed over time especially as the judicial branch has granted itself more power.
Similarly, one of the reasons the president has a pardon power is because he doesn't have to enforce those federal offenses. E.g. imagine that a president without pardon power instead offers "plea deals"/settlements for a $1 fine or concocts vacuously lenient house arrest enforcement.
The original constitution basically accepts that there is very little you can make a president do, and it instead formalizes what would otherwise be a gray area (it does have plenty about what he can't do). Some of this has changed over time especially as the judicial branch has granted itself more power.