Yes, but you can know it's the right thing to do, but not be able to physically do it.
The president's ability to physically cut someone open is not relevant to whether it's a good idea to use nuclear weapons or not. Him being unable to do it tells you nothing about whether they should be launching the weapons.
If the president fails the test that tells you nothing about whether the launch is the right thing to do. Doesn't that fundamentally make the test bad?