Donald Trump has declined to definitively say he will not seek an unconstitutional third term as US president. “I would love to do it: I have my best numbers ever,” the 79-year-old told reporters on Air Force One during a trip to Asia. Pressed on whether he was not ruling out a third term, he said, “Am I not ruling it out? I mean, you’ll have to tell me.”

Why all the talk of Trump 2028?

While this has been an ongoing theme with the president, the Trump Organization is now selling $50 red caps that read “Trump 2028”, appearing to promote the president as a candidate in the next election. Trump relishes showing the caps to foreign leaders and earlier this month placed them in front of Democratic leaders Hakeem Jeffries and Chuck Schumer during budget talks in the Oval Office. Jeffries told CNN: “It was the strangest thing ever.”

Meanwhile a thinktank called Third Term Project is “devoted to getting President Donald J Trump his rightful third term in office”. And in an interview last week with the Economist magazine, Maga guru Steve Bannon said: “Trump is going to be president in ’28, and people ought to just get accommodated with that. At the appropriate time, we’ll lay out what the plan is. But there is a plan.”

But what does the constitution say?

The 22nd amendment states in part: “No person shall be elected to the office of the President more than twice.” The amendment was ratified in 1951 after Franklin Roosevelt broke with a self-imposed two-term limit set by presidents since George Washington, the nation’s first.

Roosevelt, a Democrat who was president during the Great Depression and the second world war, served a third term and then died months into his fourth term in 1945.

Wayne Unger, a law professor at Quinnipiac University, told the Reuters news agency that the constitution is clear: presidents are limited to two terms of four years each. Unger said that while that had not been tested in court, any challenge by Trump would likely be unsuccessful. “I would predict the supreme court to say nope, it’s clear, two terms of four years each, Donald Trump, you cannot run for a third.”

Could Trump’s allies change the constitution?

Ronald Reagan publicly supported repealing the 22nd amendment, telling an interviewer that he “wouldn’t do that for myself, but for presidents from here on”. But that is a very long shot in an era of hyper-polarisation between Democrats and Trump’s Republican party.

Any constitutional amendment would require two-thirds support in the House of Representatives and Senate or a convention called by two-thirds of the states, and then ratification by 38 of the 50 state legislatures. Republicans hold a razor-thin 219-213 majority in the House and a 53-47 majority in the Senate. Republicans control 28 state legislatures.

In January Andy Ogles, a Republican congressman from Tennessee and ardent Trump supporter, proposed changing the 22nd amendment to allow people to serve three non-consecutive terms as president. Since Trump’s terms starting in 2017 and 2025 were non-consecutive, the amendment would allow him to serve a third term starting in 2029.

Could Trump run as vice-president then take over?

Trump’s allies argue that the 22nd amendment only explicitly bars a person from being “elected” to more than two presidential terms but says nothing about “succession”.

On Monday, however, Trump dismissed the idea that he could run as vice-president and then have the candidate for president resign immediately after taking office, which would return him to the presidency. “I’d be allowed to do that,” Trump said in an exchange aboard Air Force One before adding: “I think the people wouldn’t like that. It’s too cute.”

However, Trump is barred from running for vice-president because he is not eligible to be president. The 12th amendment to the constitution reads: “No person constitutionally ineligible to the office of president shall be eligible to that of vice-president of the United States.”

Are there any other loopholes?

Another theory is that Trump could become speaker of the House – which does not necessarily require him to be a member of the House – and ascend via the Presidential Succession Act if both the president and vice-president are incapacitated.

While theoretically possible as a non-elected path to the presidency, this has never been tested and would face immediate supreme court challenges. Scholars such as Unger predict that the court would rule it unconstitutional because the 22nd amendment’s intent is to limit total service, not just elections.