I don't know why you're asking me to answer questions that are clearly personal to you, and have no objective answer.
All I can say is, probably not none.
And maybe a note on diminishing returns, in that we might want to reflect on the eradication of smallpox and the near total eradication of polio, and what it has meant to you and to your community to not really have to worry about those diseases.
If it is clearly personal and you do not have an objective answer then let this be a cause we can choose to donate to based on our personal assessment.
How much are you willing to pay for screening a very long list of diseases - both in administrative costs and traveler time wasted? Will you be quarantining citizens too, as some infections have an incubation period before they can be detected - who will pay for all of that? How many tourism dollars will be lost due to this additional friction?
Now that we have established you're willing to pay to prevent diseases spreading to the US, why do you think that screening at the border is superior to reducing the worldwide incidence, or eradicating them and never having to screen for them ever again?
There is no upper bound here. The eradication of smallpox is money saved and suffering prevented every day for as long as humans are around.
Border screening clearly has a high failure rate, our recent experiences with this should be fresh in your mind. Besides threatening public health domestically, outbreaks in foreign nations are nevertheless a major economic liability. If COVID had never left China, we would still have seen a huge worldwide disruption, for example.
And anyway, screw them, we got ours is a shit perspective. Empathy should be part of the conversation when talking about so much suffering and death.
This may surprise you, but US citizens travel. And US citizens get sick in other countries. Unless you want to argue that we should take away rights from US citizens and either prevent them from entering the country, unlawfully detain them or prevent them from leaving.
You sure know the concept of incubation time. Barring infected persons from entering if they have no symptoms is not possible.
And quarantining every single person who enters is also not possible.
I'm not going to pay for quarantine. I'd like my tax dollars to go elsewhere, per your recommendation. Maybe you can make a charitable donation instead?
With RFK you're going to see huge populations of unvaccinated, border control won't help in that scenario with how contagious it is, but immigrants will provide a scapegoat. RFK is probably going to push for removing MMR vaccine requirements for legal immigrants too. His organization got many killed in American Samoa from measles.
All I can say is, probably not none.
And maybe a note on diminishing returns, in that we might want to reflect on the eradication of smallpox and the near total eradication of polio, and what it has meant to you and to your community to not really have to worry about those diseases.