Mike Lee is a "centrist". At CPAC Dallas he was visible following Ted Cruz around. Ted Cruz is a "centrist" too. Both are lawyers with notions of US Constitutional Supremacy. That is what being a "centrist" in the USA means. That is antithetical to extreme right wing "nationalist" or"racial" or"corporate" dominance of our politics, with an idea of rule of law that includes the US Constitution as most Americans expect. Trump is a "centrist": too. Most Union workers are "centrists" as well.
Marxists and Fascists are not "centrists". Used to be that the "Chamber of Commerce" sort of Republicans and the general pro-people Democrats were all centists.
People who want to overthrow this system and replace it with Communism however relabeled or reconceived, and Fascists who want to ditch the US Constitutional concepts of human rights in favor of a "better world" under centralized authoritarian rule are not "centrists".
However, it appears that the rhetoric is changing, always, under ideological or agenda pressures. I used the term "centrist" on Lee in an actually disparaging way because of his being influenced by today's (and the last 50 years') Waswhington DC establishment, by big bank interests, by big tech interests, and by CFR indoctrination, and by Chief Justice Roberts and other pretend conservatives. He's a globalist like the Bush club, and like the LDS Church.
These trends in thought do not absolutely refer to the US Constitution or the innate human individual rights once protected by the US Constitution.
I offer a better view of the world that is not a wholly-owned subsidiary of any cohesive "interests" financial or ideological. My grandfather despised Republicans as being owned by special interests/business, worked for the Democrats as the means of upholding citizen interests. Bill Clinton betrayed that kind of "Democrat" and sold out to the Rockefeller interests and plans.
Republicans generally the "Party of Lincoln" betrayed Lincoln's ideals within minutes of his assassination. While the "Democrats" are reputed to have been "pro-slavery" there was also a notion of federalism, meaning decentralized power with local governments having the highest possible power. Most of the the support for the south during the Civil War was manipulated by British interests into a po-slavery single issue, while in the North the same foreign intersts manipulated the abolitionist cause. The intent was to break up the United States and then limit growth westward by taking the Mississippi into British control, and break off the states one by one and reassert British management.
What did happen was a financial takeover by British finance and progressive ideology. The CFR today is very much compliant with British globalist interests. It's literally the modern British form of Empire.
Russia and China have some thoughts about asserting "better management" but largely, today's politicis is a qeuistion of who's gonna handle the British lion.
People like Cruz and Lee are stooges for the way things are. Trump is just accidentally more of old-time American democrat, being himself most of all. He is a direct threat to "the way things are" but he has found a very strong political base in American values largely held by common Americans.
The problem with Trump is he's his own man.