Democrats are warning members of their party not to fall into a political trap after President Trump ordered an investigation into former President Biden’s mental state and executive actions at the end of his term.

Donald Trump has issued a Presidential Memorandum directing his administration to probe whether former President Joe Biden was truly in charge of the United States, or if key White House aides were involved in a "conspiracy" to usurp executive power due to his perceived "cognitive decline".

As Donald Trump launches an investigation into Joe Biden, it's the third time the Republican has engaged in such a flagrant abuse of presidential power.