Is American Exceptionalism - often cited by politicians on the stump - an actual thing any more? If so, what is it, exactly?

if you look at other nations of the world, even the "advanced" first-world ones, you will note several subtle but very important distinctions:

1) their government charters exist to DEFINE State powers... ours specifically exists to LIMIT State powers...

2) their people see themselves as SUBJECTS of the State...Americans ARE the State...

3) if over the last 300 years that nation experienced a popular revolution, count how many ended up under tyrannical rule again within 20 years, vs. the American system that has persisted for over 200...

4) count the number of nations where you can enjoy all the benefits and privileges of full citizenship simply by right of birth..

in short, the very fact that so many here grow up in such luxury that they can ignore, belittle or deny American Exceptionalism.....even as tens of thousands from other nations risk everything every year to experience it (willfully passing through numerous countries that rank higher than us on those various "happiness indexes" ...by the way) is part of what makes us "exceptional"....

Yes, it is. America celebrated it during the magnificent parade and moving, powerful speech by President Trump on Independence Day.

Most nations believe themselves to be exceptional. America gets a lot of slack about that belief because they are the most powerful and wealthy and as such it can come off a bit egotistical to tell everyone that you are the best. It is like the prettiest girl in school that tells everyone that she is the prettiest, or the best sports star on campus that spends too much time telling you how great his performance was in his last game. It would get old really quickly.

We're the most powerful country in the history of mankind. I'd say that's pretty damn exceptional.

Yes it is a thing. It's when one individual performing an aggressive dance causes another individual's body to contort, snap and break with every dance movement that the first individual performs.