Not a coherent philosophical ideology like Marxism or Liberalism or even some varieties of Conservatism.
But yeah, Trump does have ideas that people respond to. All of them really bad ideas speaking in a moral sense, a technical sense, a Poli. Sci. sense and so on. And of course by focusing on the latent issues of Trump's ideas, what's there on the surface, that doesn't discount stuff that's hidden or suppressed, namely white supremacy, and white grievance.
Speaking in the most value neutral sense, Trump's ideas are:
-- Make America Great Again, i.e. America is in decline, that the present of America is significantly worse than the past.
-- America First, i.e. globally America is losing to emerging powers and economies and that America's economy must benefit itself over others.
-- Citizenship is a privilege to be doled out to the chosen few.
These are the overt ideas of Trump. And they fall under what's been called "herrenvolk democracy" (
https://en.wikipedia.org/wiki/Herren...ated%20concept.) The word Herrenvolk by the way means "Master Race". Trump's idea is that America's democratic rights are aristocratic, meant for the few and not egalitarian. That's quite analogous to Nazism. A lot of people say National Socialist Workers Party and use that to claim spuriously that Nazis were socialist but what they don't get is that in Nazism you had socialism for the aristocratic few, as an aristocratic privilege for the few and as a way to dole out loyalty to exclude the oppressed and needy.
In the most neutral sense, Trump's ideas do in fact respond to, or let's say intersect oddly with, issues in the real world. The sense of "America is in decline" and "America is significantly worse than the past"...Trump has obviously exaggerated that disproportionately and lied about it maliciously and so on, but in a broad sense after the failure of the W. years, where America saw its prestige fall sharply in a way that was only partially recovered by Obama, you no longer have the confidence in America despite political rhetoric that they should or could act unilaterally. Obama's refusal to intervene in Syria, his N-Deal with Iran, great stuff by the way, was born out with that. The thing is that Obama could never admit, because it would be political suicide no matter how moral and correct it is do so, that
a) America is and has been an Empire for a century and more,
b) Americans don't like to admit they are an Empire. That's not the same as "not liking being an Empire" (which I think Americans do like).
c) America should try and come up with ways to not be an Empire anymore, which Obama tried to do but without doing a) and b). You can't be half-Disraeli and half-Mandela, my dude. So that meant that Trump could paint Obama's multilateralism as a sign of America's decline in the world stage.
Likewise "America First" and so on, globalization and so on is an easy enough villain for both the right and the left, and Trump's response to that which is a radical nativism is obviously false but again a real problem in society can have both a right-wing and a left-wing response. The Taliban and various fundamentalist outfits in the Middle East are quite valid in responding to imperialism and colonialism of various kinds but they are a right-wing extreme response to that real problem, and the problem in the Middle East is that there aren't significant left-wing alternatives of comparative political force. One of the few was the Kurds and now that's gone.
The question of citizenship...well that's just nonsense, but it's a logical enough escalation from the two.
So I'd say that's the ideology of the Trump base and Trump himself.