From the courts to the campaign trail, former President Donald J. Trump is challenging a hallmark of American-style democracy: its suspicion of concentrated power.

The Supreme Court will hear arguments on Thursday over Mr. Trump’s claim that criminal charges against him in the federal election subversion case must be thrown out because the Constitution makes him all but immune from being prosecuted for actions he took as president — no matter what the evidence may show.

That vision of a presidency operating above the law dovetails with second-term plans that Mr. Trump and his allies are making to eliminate myriad internal checks and balances on the executive branch and to centralize greater power in his hands. That would include eliminating independent agencies and job protections for tens of thousands of senior civil servants.

While the legal theories behind Mr. Trump’s claim of absolute immunity and his plans to consolidate White House control are different, they are united by a common approach to governance. The power of American presidents has traditionally been seen as held in check by counterbalancing forces, but Mr. Trump is trying to grind down such constraints.

As he once declared to a cheering crowd of supporters in 2019, referring to the portion of the Constitution that creates and empowers the presidency: “I have an Article II, where I have the right to do whatever I want as president.”