White Supremacist
Intended to be a pejorative term, but without having a specific definition so that its use is easier to defend.
The term is composed of two somewhat neutral terms. White refers primarily to the Caucasian group of ethnicity, Hispanics excluded (according to post-modern nomenclature). There is nothing in the definitions of these terms to imply inherent badness. Negative connotations creep in as a result of the progressive movement's judgments of European and American history. The term "nationalist", neutral on its own, takes on negative connotations when compared with progressive ideals of multilateralism and internationalism.
Left unsaid, of course, is the implication that "white nationalism" "really" refers to white supremacism in combination with ultra-nationalism, but reaching that conclusion is more a matter of ideological choice than an ideally apolitical judgment of history. The negative connotation of Nazism, Fascism or other historically significant examples of white supremacy movements is left in the background as something to rally progressive interest groups to the cause. This schema tends to be effective because progressive "foot soldiers" have been conditioned to think of all forms of "white nationalism" to be essentially the same thing. And, of course, in politics, in the absence of rational dialog in the public arena, few techniques work as effectively as fear mongering.
It should be acknowledged, of course, that nationalism inherently involves a bias in favor of one's own nation. Merriam-Webster declares nationalism to be "loyalty and devotion to a nation; especially : a sense of national consciousness exalting one nation above all others and placing primary emphasis on promotion of its culture and interests as opposed to those of other nations or supranational groups." This definition adds to the definition of "patriotism" which is, "love for or devotion to one's country." Thus, the term "American exceptionalism" would be used by an American nationalist, but not necessarily by an American patriot. It's natural, of course, for someone to conceive a love for America (or other native country) based upon seeing its history and/or culture as in some way superior to that of others. It's fairly easy for Americans to list such historical events and such cultural features. It's also easy to list negative events and negative cultural features. It's a matter of judgment to discern what outweighs what.
It should also be noted that there are distinct advantages and risks entailed with "going it alone" or in combination with other nations or even with the U.N. In fact "cooperation vs. competition" remains an active area of research in game theory. Numerous examples of world-wide risk have been proposed as reasons to insist on internationalism, even, to use a more current term, globalism. Such matters are, of course, worthy of serious consideration and dialog. Unfortunately, that consideration and dialog are increasingly problematic in our increasingly polarized society.
Needless to say, the reflexive resort to catch-phrase pejoratives tends to diminish, not invite, responsible reflection and dialog.