Maui, I am particularly interested in your answer to this section of my reply to you previously:
"For the individual hallucinating and fantasizing about killing the president, I would agree that this person should not be allowed to have a gun. This is an example of my point that no right is absolute and individual exceptions can be made in certain circumstances. Now my follow up question is, how are we to restrict this individual from buying a firearm if we are unable to perform any type of background check? How are we to take away a firearm already owned by this individual unless we know he has a gun (gun registration)? I am not trying to make the case that we need more background checks in Hawaii but I feel that these are strong arguments being made by those who do want to maintain or add more regulation and I don't have a good answer. How can we stop a person or people who should not be allowed to own a firearm from owning a firearm if any system that regulates firearm ownership is deemed unconstitutional?"
The problem with the generic term "background check", it could entail too little or too much personal information, none of which is guaranteed to prevent the purchase of a firearm in and of itself.
HPD and other public employees, unless already trained and experienced in another job, do not have the professional skills to determine the mental capacity of any one individual. That's why the courts seek out professionals in those areas for things like ability to stand trial and assist in their own defense.
HMOs and private doctors not having an occasion to discuss your life and all your problems have no idea what's going on inside your head.
So what do they do? They look for markers. They flag people for further interviews and, if warranted, treatment. The flags may or may not indicate a problem with someone's mental condition. They simply help screen people for additional followups.
Using these flags to prevent someone from exercising their rights is another preemptive punishment. Without actually diagnosing someone, you have summarily stripped them of a Constitutional right because a flag gives you suspicion ... nothing more.
If it comes to the guy hallucinating and actually telling people he plans to kill someone, president or not, then the people he tells should be responsible for making a report to police. If they don't, then why is it now a problem for government? Government can not, and should not, be making rules and doing background checks simply because citizens don't take responsibility to warn of danger.
For owning a firearm, it should be a very quick and simple check: identity, local and federal criminal history especially outstanding wants and warrants, TROs, other domestic complaints, and what I call black ball entries. If a customer has been diagnosed as being mentally unfit to own a firearm, that MUST be in the NICS file. If it's not, that's a failure of the CURRENT system.
Did you watch the testimony before Congress when Gabbard's husband, Mark Kelly, spoke after Sandy Hook? He testified one of the things his group found out is we have a gigantic backlog of unentered data regarding psychological evaluations on patients. Basically, if NICS doesn't get updated, the doctor's recommendation to keep you from buying guns can't stop you. That's one reason we now have laws that let HPD go directly to doctors and HMOS to ask the question. If the system worked as designed, that extra burden, cost, and point of failure would not exist. It's yet another example of how government, especially politicians, don't fix problems. They just create a new law to work around it and the rest of us have to live with it.
So, in that respect, let's break down your question. Is the problem that the guy bought a gun? That's only one avenue of getting guns, so even the best background check in the world that prevents him from buying in no way guarantees he can't ever get his hands on a gun (see "Adam Lanza" for how that conclusion is supported). We can't guarantee he can't get a gun.
So now what? Can we lock him up? Only if someone reports they heard him make the threat and it's deemed credible. Or if he demonstrates he is a danger to himself or others in some way. Unless that happens, we can't just lock him up for no reason.
Where are we? We can't lock him up if we don't know he's dangerous, we can't stop him from buying guns if we don't know he's dangerous, and we can't guarantee he can't get guns outside the normal retail FFL process.
I guess the only thing left is be prepared for an attack, and hope it never happens. Sound familiar? This is what 2A is all about. Self defense is YOUR responsibility. Not the government, and not the mental health industry. As Jdelacruz said, the President has protection because they full well know all threats can not be stopped preemptively. Sometimes you have to be able to meet force with force. This same protection is what the background and firearms laws seek to infringe on: our individual right AND responsibility to defend ourselves. I'd love to hear of the Secret Service being told they can't carry weapons for 2 weeks until they all renew their permits. You think Obama would venture out during that time?
And remember, even though any government official or celebrity can be at higher risk from loons because of their public exposure, it in no way makes their lives more valuable than yours or mine. We deserve the same right to protection regardless of the probability of being targeted. If that means they get to hire professionals, and we are required to use the DIY method, I'm fine with that as long as they stop trying to reduce the number of options I have at my disposal!