My unpopular opinion: fascism was much more mainstream in the days of Sen. McCarthy, or even during the administration of Pres. Trump. Trump himself is increasingly making common cause with fascism, and others such as Carlson and Bannon flirt a lot with it; the cover-up of the quasi-fascist putsch attempt on 1/6 is widely participated in by Congressional Republican leadership; but by and large the Republican leadership is less susceptible to fascism, which has never been popular with more than a tiny fringe of the Republicans' mass base.
My characterization of political figures mentioned in this thread (and I think the conceptual distinctions are important):
Joseph McCarthy: fascist
Donald Trump: right-wing populist
Tucker Carlson: rightist
Viktor Orban: rightist
Jair Bolsonaro: right-wing populist
Steve Bannon: rightist
Lauren Boebert: right-wing populist
Marjorie Taylor Greene: ultrarightist
Madison Cawthorn: conservative
Kevin McCarthy: conservative
with brief descriptions of how I'm using the terms
fascist: a reactionary middle-class-backed violent mass movement that aims to smash organized labor and radically transform the country by making frequent participation in state administration compulsory, merging the fascist mass movement with the state, and drawing every aspect of life into the state's orbit; it draws the lumpenproletariat into its orbit out of despair, becoming increasingly left-wing in rhetoric, then trims its sails in the direction of conservatism in order to get the financial backing of the upper-class sectors needed to gain state power, after which it begins to purge the mass (ochlocratic) element and transform itself into a conservative regime.
right-wing populist: a reactionary middle-class-backed mass movement that elevates a Bonapartist "man on horseback" figure who succeeds through demagogic appeals to popular resentment, particularly against labor, the left, and the most vulnerable; it draws in the right wing of the working class but the elites tend to make common cause with them only when they are too popular to ignore; such movements make frequent overtures to other mass and elite movements both on the right and on the left
rightist: the reflection in lower-class circles of the reactionary politics of the elite, amplified by the financial backing from elite circles; it tends to be a halfway point between conservatism and fascism or ultrarightism, and is typified by positions on many issues that are well to the right of the conservative mainstream which are held with pride on ideological grounds, while sometimes demagogically making overtures to the far left. Socially these often violent movements gain support among middle-class layers as they become personally afflicted by capitalism, and as the right win battles in the Beltway and on the street, and in the long run they tend to end up in the ultrarightist/fascist camp. They tend to be supporters of right-wing unity and can get along publicly with any other given right-wing tendency (although they can also get into ideology-driven feuds with people with almost identical opinions).
ultrarightist: a violent reactionary lower-class movement that is committed to right-wing aims and fully under the direction of the upper classes that systematically forces battle with people who interfere with the profits of the upper class, whether that be organized labor, comparatively left-leaning politicians, independent women, or members of oppressed races who are in the line of fire. As these movements grow in strength they are always pulled in the direction of fascism as they begin to attract middle-class support so as to contend with the conservatives for direct control of the state. They cannot exist without conservative backing but publicly the conservatives and ultrarightists are very much at odds.
conservative: a mostly upper-class movement with generally right-wing positions, opposed (though their financial backers are not always) to the radical tendencies of the populists, rightists, and fascists. Conservatives win some middle-class and lower-class support through dissatisfaction for one reason or another with the politics of the left, but does not have the passionate popular base of these radical movements. They will make common cause with right-wing radicalism to frustrate left-wing radicalism, though.