Donald Trump has a warning for Joe Biden as the Supreme Court prepares to weigh Trump's high-stakes case on presidential immunity.

If the court find that presidents do not have immunity from criminal prosecution, "Crooked Joe" could be in trouble as well, Trump wrote on Truth Social.

"If they take away my presidential immunity, they take away crooked Joe Biden’s presidential immunity," Trump warned.

Trump's warning for Biden

Trump opponents are hoping for a swift rebuke of Trump's argument, which they say is just a fig leaf for a sweeping, almost monarchical assertion of presidential power.

But Trump has argued that immunity is necessary to leave presidents free to perform their duties without fear of retaliation from political opponents.

Presidents would become merely "ceremonial" figures without protection against abusive prosecution, Trump says.

"Without presidential immunity, it would be impossible for a president to properly function, putting the United States of America in great and everlasting danger!" he wrote.

The Supreme Court will weigh arguments Thursday in Trump's case, which concerns whether U.S. presidents have immunity from prosecution for "official acts."

Presidents are already immune from civil liability for official acts. Trump argues the same shield should apply in criminal cases, which have an even greater power to cripple a president with the fear of prosecution.

"That would be the end of the Presidency, and our Country, as we know it," Trump wrote. "Obama, Bush, and soon, Crooked Joe Biden, would all be in BIG TROUBLE."

Could Trump turn the tables?

Democrats have characterized Trump's immunity argument as self-serving and cynical, but his concerns are far from outlandish in an increasingly chaotic political climate that has tested the guardrails of democracy.

In fact, Trump's own opponents have accused him of harboring ambitions to govern like a vengeful dictator if he wins in November.

Trump has threatened to seek "retribution" against his enemies, whom he accuses of violating democratic norms by orchestrating a "witch hunt" against him.

The Democratic party's lawfare, Trump argues, is setting a precedent for Trump to turn the tables if he returns to the White House.

While it's unclear how the Supreme Court will react to Trump's immunity claim, the court echoed his concerns about the dangerous consequences of unchecked partisan lawfare when it rejected, unanimously, an effort to take him off the ballot last month.