Which is most likely to happen and greatest threat to the future of America?

OK I really don't want to bait but really curious on which you think and your reasons why and predicted events.

My personal opinion is the threat of Immigration. Very concerned that with the coming cold months that numerous deadly infections that will not be treatable are coming to kids that never been exposed to such illness.

The sociologic-economic train of the integration could deal a crushing blow. If not devastate strain so much that any other event would be the undoing of America as we know it.

Also we know the great majority are going to cause a pandemic of amazing proportions on the illegals already hear, the legal immigrants, low-skilled low-wage and minority populations. This will result in a skyrocket in crime and overwhelm the prison system beyond anything we have seen before.

Just my two-cents, but hey its free!