The Supreme Court heard oral arguments last week on former President Donald Trump's claim of presidential immunity from criminal prosecution -- a claim that was vehemently opposed by federal prosecutors and rejected by a district court judge and appellate panel in Washington D.C.

Justice Brett Kavanaugh expressed some skepticism toward the lower courts' total dismissal of Trump's immunity claim -- a position that may have been prefaced 15 years earlier in an article he published in a law review journal, according to Newsweek.

In that article, then-Judge Kavanaugh argued that sitting presidents -- and presumably former presidents, to an extent -- needed special immunity to protect them from potential prosecution so that they could perform their duties without fear of imminent or future legal consequences from partisan opponents.

Presidents need immunity to perform their duties effectively

In the 33-page article for the Minnesota Law Review, future Justice Kavanaugh explored the notion of separation of powers in the federal government and put forward several proposals for how to fix some of the biggest issues that resulted in the bipartisan and perpetual lament that "Washington is broken."

One of those ideas was how "sitting presidents" deserved immunity from prosecution and the ability to defer civil and criminal cases and charges until after their term concluded, as appropriately enacted through congressional legislation, given how difficult and taxing the job of the presidency was based on his prior experience working in the White House.

Kavanaugh went further and offered up a defense to two likely critiques of his idea, the first being that such immunity would effectively elevate a president "above the law," though he disagreed with that assessment and wrote, "The point is not to put the President above the law or to eliminate checks on the President, but simply to defer litigation and investigations until the President is out of office."

Impeachment the remedy for a "bad-behaving or law-breaking President"

As for the likely critique that prosecution served as "a check against a bad-behaving or law-breaking President," he countered, "the Constitution already provides that check. If the President does something dastardly, the impeachment process is available."

"No single prosecutor, judge, or jury should be able to accomplish what the Constitution assigns to the Congress. Moreover, an impeached and removed President is still subject to criminal prosecution afterwards," Kavanaugh wrote.

"In short, the Constitution establishes a clear mechanism to deter executive malfeasance; we should not burden a sitting President with civil suits, criminal investigations, or criminal prosecutions," he added. "The President’s job is difficult enough as is. And the country loses when the President’s focus is distracted by the burdens of civil litigation or criminal investigation and possible prosecution."

Is there a substantial immunity difference between "sitting" and former presidents?

To be sure, Newsweek observed, Justice Kavanaugh's law review article from 15 years ago dealt with immunity for "sitting" and not former presidents, but still likely provides a clue for where he will stand on the question of former President Trump's claimed post-presidency immunity from prosecution for acts that occurred while he was still in office.

University of Houston law professor Alex Badas told the outlet, "Trump is currently out of office, so that might alter how he views Trump's claims of immunity," and further explained, "It is unclear whether Kavanaugh would expand that view to include former presidents who are running for office or not."

"If so, it could create a loophole where a president like Trump could simply declare that he is running for office every four years to avoid facing any form of consequence for his actions," he added.

Kavanaugh could support the idea of partial immunity for former presidents

Badas also downplayed the idea that Kavanaugh's 2009 article gave any clear indication of how he might decide the current case involving Trump, given the fact that such law review submissions tend to be broad-based and not narrowly focused like a specific case, not to mention the fact that the justice was not bound to adhere to what he wrote 15 years ago and could have changed his mind since then.

That said, analysis of last week's oral arguments duly noted that Kavanaugh was skeptical of the lower courts' rulings and did seem to suggest through his various questions that he would support a decision extending at least partial immunity from prosecution to former presidents for acts during their tenure that fell within the realm of their official duties.