For example, for decades we kept Communists or those with Communist affiliations out of the military or government. Political Correctness and aggressive legal prosecution has now overwhelmed the attitude we used to have that some people were possible national security threats or not the best choice for other reasons, so it was best not to take the chance and err on the "safe" side.
The rest of the steps needed will then follow if you give it a bit of thought.
But to take them, we need to cast aside thirty years of accumulated PC attitudes, Liberal Law and thorough indoctrination. This will be one of the toughest jobs this country has ever accomplished. We now have a majority of the country thoroughly indoctrinated and accustomed to it. Most have never known anything different. It is accepted from the nearest Kindergarden to the farthest business and government office. PC is completely entrenched and rooted in law, regulation and public attitude. It will be the toughest thing we have ever rooted out of our national more system, including slavery.
This single incident will not do it. It will take much more. Look how we have still held onto our mistaken predispositions concerning our Political Correctness, despite the horrors of 9/11! Our society is now based on the principle of a devious and unAmerican lie.
If you catch them before they do damage you court martial them and kick them out - as should have been done once he uttered the 'rape our women' comment. At this point he should just be shot.