The former president made the comments during an appearance on CBS Monday, noting that he has not been the biggest fan of Mr Trump’s, but that Mr Bolton’s naming to such a key national security position is a major step in the wrong direction.
“I have been concerned at some of the things he's decided. I think his last choice for national security adviser was very ill-advised. I think John Bolton has been the worst mistake he's made,” Mr Carter said.
Mr Bolton is a controversial figure, even within the Republican party. The former ambassador to the United Nations under former President George W Bush, Mr Bolton has criticized the Iran nuclear deal brokered by the Obama administration, and has called for preemptive strikes against North Korea.
Mr Carter is not the only former president to criticise Mr Trump’s actions as president. Former President Barack Obama has frequently provided something of a counterweight to his predecessor, and former President George HW Bush has made his displeasure with Mr Trump known.
Mr Carter noted during the interview that he does not want to see Mr Trump impeached, even if special counsel Robert Mueller — who is leading an investigation into Russian meddling in the 2016 election and whether the Trump campaign was involved in any way — finds that the president acted incorrectly.
Instead, Mr Carter said that he thinks that Congress and the Supreme Court have enough power to check the president without the extreme measure of impeachment.
The last president to be impeached was President Bill Clinton, who was not removed from office after the Senate voted on the issue in the late 1990s.