I think the odds are better than even that Trump will use a tactical nuclear weapon

sometime in the next four years.

The probable target would be a perceived or real ISIS stronghold in Iraq.

Trump is, deliberately or not, systematically gutting all conventional (and rational) ways of dealing with ISIS. He's downgraded the role of the Joint Chiefs at intelligence briefings, undermined the role of the intelligence services in general, compromised (with his Muslim ban) all those in Iraq and elsewhere who might feel motivated to cooperate with the US, and with the rumors now of backdoor communications with Russian intelligence (resulting in the outing of alleged US sources in Russia) made it less likely for foreign intelligence services to share information with the US.

All this increases the likelihood of a successful attack on the US homeland, AND makes a conventional military victory against ISIS exponentially more difficult. Having promised to destroy ISIS within months of being elected, having said he "knows more than the generals" and having been quoted as asking at briefings, repeatedly, "Why can't we use" nukes?, I think the use of one or more tactical nuclear weapons in the Middle East is now possible, indeed probable, unless something drastic happens to forestall this.

The effect of course would be catastrophic, aside from the tens if not hundreds of thousands of civilian casualties. The US would lose all support everywhere in the world except among hardened right wingers and racists in the US, Europe, and Israel. The vast majority of the world's people will see us as mass murderers. Our political alliances would be in shreds. The backlash will be fierce, but Trump and his supporters will lay this out as "us against them" and try to rally support in the US, including using the tools of the national security state to infiltrate and suppress dissent.

I have no idea how or if we can stop this, or what a rational, effective response will be. I'm tossing this out here simply so people can begin thinking about these possibilities and start formulating strategies to meet it.

Whatever happens, we are in for very tough times. American democracy, such as it is, will be tested in a way it hasn't been since the US Civil War.

How different things would be if only we didn't have that GD Electoral College--270 mostly white, mostly male, mostly affluent political hacks, choosing our president, as opposed to the clear majority of millions of voters.

Best wishes to all in these very hard times.