Speculation continues to mount that Donald Trump, who turned 75 on Monday, will become the first American president to be impeached twice to seek another term in the Oval Office.

Besides the two impeachments, Trump’s place in U.S. political history is already marked by other notables: first president to be acquitted after two impeachment trials; first president to run for reelection — and lose — after being impeached; and the first Oval Office incumbent to lose a reelection bid in the 21st century.

Another Trump campaign would almost certainly revive memories of the deadly Jan. 6 riot at the U.S. Capitol earlier this year, when pro-Trump supporters stormed the Capitol while Congress was attempting to certify the results of the previous presidential election.

Facebook has suspended Trump’s accounts for two years following its finding that he stoked violence ahead of the insurrection.

Trump is already facing the most serious legal threat of his career. New York prosecutors have convened a special grand jury to consider evidence in their criminal investigation into his business dealings — seen by many as a sign that Manhattan District Attorney Cyrus Vance Jr. is moving toward seeking charges in the two-year, wide-ranging investigation that has included scrutiny of hush money payments, property valuations and employee compensation.

Trump has slammed the probe as “purely political,” and those around him insist he isn’t concerned about potential legal exposure even as they suggest his political posture is evolving.

“I have definitely picked up a shift that there’s more of an intentionality to be leaning on the side of it’s going to happen than it’s not,” said Matt Schlapp, chair of the American Conservative Union, who is close to the former president. “It’s a very real possibility.”

Trump would be 78 on Inauguration Day in 2025 — the same age as Democrat Joe Biden on his own Inauguration Day this year — and multiple Republicans are already making moves for runs of their own. Trump’s former vice president, Mike Pence, has already visited the early-voting state of New Hampshire.

Trump’s team is planning rallies this summer to test his political strength, according to The Associated Press. His advisers are also reportedly eyeing events in Ohio, Florida, Alabama and Georgia to bolster midterm candidates and energize voters.

Allies say Trump misses the office and is eager to return to the action — especially as he sees other potential candidates making moves. He has also felt emboldened by some recent developments, including the ouster of one of his chief critics, Republican Rep. Liz Cheney, from her House leadership position. And some see the presidency as offering potentially useful legal shelter as investigations into him and his family business intensify.

“There’s a continued, enduring interest and folks encouraging him to run in 2024, but he’s in no rush to make a decision. And he’ll do that at the appropriate time,” said Trump spokesperson Jason Miller, who reportedly is leaving that position soon.

There’s no constitutional or legal mechanism for Trump to return to the presidency absent winning another election in 2024. After House Democrats impeached him for the second time only hours before he was set to leave office, they hoped a Senate conviction would prevent Trump from seeking another public, elective office. That didn’t happen, with the Senate again acquitting him.

Despite his loss, Trump remains a commanding force in the Republican Party A recent Quinnipiac University national poll found that 66% of Republicans would like to see him run for reelection, though the same number of Americans overall said they would prefer he didn’t — and there is no evidence that he has grown any more popular since losing by more than 7 million votes in November.

Supporters in early-voting states are anticipating another Trump run, even as other would-be contenders, including former Secretary of State Mike Pompeo and Arkansas Sen. Tom Cotton, have been making visits.

“He’s definitely laying the groundwork, keeping his powder dry for a run,” Josh Whitehouse, a former member of the New Hampshire House of Representatives who worked for Trump’s campaign and administration, said of the former president. “I’d expect nothing less, knowing who he is and having worked for him for so long.”

While voters will certainly hear out other candidates, he said that, at the end of the day, support will coalesce around Trump if he decides to run.

“The energy’s still there,” Whitehouse said. “You can’t replicate it.”

The Associated Press contributed to this report.