Top methods of suicide <link>:
[ul]
[li]firearm, 50%[/li][li]suffocation/hanging, 25%[/li][li]poisoning, 17%[/li][li]falling, 2%[/li][/ul]
I think suicide is, to an extent, "informable". Some societies accept it more than others. From a National Academic Press [book](https://www.nap.edu/read/10398/chapter/8): "Cultural variables have a far-ranging impact on suicide. They shape risk and protective factors as well as the availability and types of treatment that might intervene to lessen suicide."
Removing the number one self-harming aid from those who are deemed likely to use it to that end makes sense. Another, parallel, approach would be PSAs, influence campaigns, discouraging the act, and encouraging help-seeking. I'm thinking ad spots etc aimed at vulnerable populations, accompanied by community resources, outreach phone numbers and websites and so on. And since guns are so popular for this action, they get included in the ad/PSA spots themselves--for instance someone obviously depressed has a gun on a nearby dresser, and a phone nearby, and the tagline is "Pick up the phone, not the gun." with a phone number for a suicide prevention hotline.
Like Richard, I won’t debate the merits of Heller and the individual right to keep and bear arms here. Suffice it to say that it is a settled issue for now.
With that being the case, it seems that SCOTUS has established it as a fundamental right. Under most circumstances, fundamental rights can be taken away only after a criminal conviction. So while clear and convincing evidence is a high bar, it’s not as high as the reasonable doubt standard which should apply.
We’ve done civil forfeiture laws to death here. In most jurisdictions, the citizen has the burden of proving that assets were wrongly seized. Hiring an attorney to contest a forfeiture is rather difficult if the government has taken all your money away, and the cost of challenging a forfeiture can easily exceed the amount at issue. I don’t really see how this is relevant to the thread, although I suppose a firearm could be seized using forfeiture proceedings.