Irresponsible use of nuclear weapons, over which he has sole authority.
Close to zero, but a tiny increase in the likelihood of such a catastrophe is still grounds for a lot of concern. If something is at a trillion on the badness scale, a thousandth of a percent increase in likelihood is still a lot of risk.
Abolishment of major government agencies, including the FDA, EPA, DoE, etc.
Actual abolition? Next to zero. The agencies might be gutted, but the names will be kept around to lend authority to whatever he does. The EPA will enthusiastically approve of his energy policy, the FDA will be kept around to approve of his gutting of Medicare and the ACA, and the Department of Education will promote his sale of the education system to for-profit charter school magnates.
Defaulting on, or demanding a haircut on, national debt.
I actually think a default will become less likely in January, simply because of single-party control of government.
Refusal to honor treaties unless payment is made.
Maybe 5%. More if he actually takes over foreign policy. I suspect we’re going to find quite soon that his State and Defense departments will look a lot like they did in 2003. This is disconcerting for a number of reasons, but not that reason.
Encouraging religious discrimination against Muslims and LGBT people through policy and Cabinet appointments.
100% or close to it. The Supreme Court might be asked, fairly soon, if anti-LGBT discrimination in the workplace is already prohibited as a form of sex discrimination. I’m pretty sure his DOJ is not going to advance that idea in front of the court. (He might personally believe it, to the extent that he believes anything, but the fossil he finds to be his AG won’t.)
Large scale deportations.
Depends on where they find the money. The deficit hawks might just rejigger the numbers and claim Obama’s record as their success.
Cancelling provisions of the ACA without any action regarding those dropped from coverage.
20% no action (I think the lunatics, not just Trump, might really drive that bus off the cliff), 79% crappy action, 1% good action.
Discouragement of action regarding global temperature changes that significantly impact the general effort to alter their rates.
100%. On the first day, at noon.
Implementing a federal abortion ban.
Maybe 20%. He won’t immediately have the ability to get that kind of majority on the court. I think a repeal or major reduction in Roe rights is more likely, maybe 40%. Herding all the various strains of right-wing justices into going along with an actual federal ban would be harder. There seems to be unanimity in right-wing legal circles that Roe is terrible, but a portion of them would also find a federal ban terrible. (And who knows, maybe John Roberts would crack under the pressure to overturn Roe too.)
Fulfilling campaign threats to silence, sue, or censor past critics.
Maybe 10%? Not sure about this, but I’m pretty sure he’s all about the shiny object in front of him. Yesterday’s critic was yesterday’s toy.
Supreme Court justices who will advance any or most of the above.
100%, with his first appointment.