The principles of TNP are subjective.
If TNP was governed by Tyr's Hand then I think it would be encouraged for the Delegate to have served in the NPA. As long as the delegate facilitates the military to do its thing then I don't think Tyr's Hand would have a problem with a non-NPA delegate.
In 10000 Islands, military service is a mandatory requirement to run for delegate. In TNP, it is not.
They key principle of TNP is that the delegate is elected by the majority of voters. As long as that happens it doesn't matter what any of the policies are, the government will keep the voters happy until it's time for a new government.