In September 2021, JD Vance offered two predictions about former President Donald J. Trump and one piece of advice.

Mr. Trump would run again in 2024, Mr. Vance said. He would win.

And when he did, Mr. Vance counseled, he needed the right people around him this time.

“Fire every single midlevel bureaucrat, every civil servant in the administrative state, replace them with our people,” Mr. Vance said on a podcast.

He continued.

“Then when the courts stop you, stand before the country like Andrew Jackson did,” Mr. Vance said, citing a (possibly apocryphal) quotation long attributed to America’s seventh president, “and say: ‘The chief justice has made his ruling. Now let him enforce it.’”

In his U-turning path from anti-Trump author to MAGA-approved Ohio senator and running mate, Mr. Vance has developed a reputation for being ideologically pliable — open-minded, supporters say; core-less, critics counter.

But he has been unswerving in recent years in his assessment of how Republicans should carry themselves when they win: Use every available lever of state, even if that means testing the bounds of the constitutional system.

“We are in a late republican period,” Mr. Vance said in 2021, stressing the need to counter what he described as the political ruthlessness of the left. “If we’re going to push back against it, we have to get pretty wild, pretty far out there, and go in directions that a lot of conservatives right now are uncomfortable with.”

For years, Mr. Vance has appeared entirely comfortable in far-out-there corners of his party, embracing thinkers and proposals on the so-called New Right. He has drawn from influences as varied as a monarchist blogger, “postliberal” conservative Catholics and Prime Minister Viktor Orban of Hungary, according to a review of dozens of speeches, interviews and writings since Mr. Vance formally entered politics and interviews with people close to him.

Through his bumpy early weeks as Mr. Trump’s junior partner, Mr. Vance has strained to combat a Democratic attack line that he is not just wrongheaded but “weird” and retrograde, prone to meditations on “childless sociopaths” and “cat ladies” and the ills of the sexual revolution.

On a certain level, though, many of Mr. Vance’s intellectual allies agree with his opponents on a core premise: He has ascended while advancing some ideas that fall well outside the traditional political mainstream, insisting that these zero-sum times require a zero-sum strategy.

He has urged Republicans to “seize the endowments” of left-leaning universities, punishing nominal ideological foes through dramatic changes to the tax code, and warmly quotes Richard Nixon’s observation about higher education: “The professors are the enemy.”

He has suggested that parents should receive extra votes in elections — one for each child in their care — to dilute the electoral power of the left. (His team now insists this was more of a thought exercise than a serious proposal.)

“If our enemies are using guns and bazookas,” Mr. Vance has warned, “we damn well better fight back with more than wet noodles.”