Ever since Donald Trump's rise to 2016-contender prominence, the rap on him, and perhaps part of his broad appeal, has been that he's not a conservative. And he's not--he's a nationalistic populist. Yet there's another way to understand The Donald's professed politics: as that of the first prominent "European-conservative" American presidential candidate. He's not so much America's next Ronald Reagan or Barry Goldwater, but her first Marine Le Pen.
A prerequisite for grasping this is understanding the true natures of liberalism and conservatism. While many have their own definitions of the latter--and will stubbornly insist they're correct--the truth is that both political terms are provisional, meaning different things in different times and places. The term "conservative" in the 1970s referred to a communist in the USSR and someone staunchly anti-communist in the US; and a European conservative today, such as Britain's David Cameron, is well to the "left" of our conservatives. Many other examples could be provided, but the point is this: liberalism and conservatism are not ideologies as much processes. Liberalism is the process of inexorably trying to change the status quo; conservatism is the process of trying to preserve the status quo. Thus, the actual positions the terms are seen as representing will vary depending on the status quo in question.