After he left office, Jimmy Carter set back the pace of nuclear arms reduction by quite a bit by telling the Soviets that Ronald Reagan was not serious about reducing them. Despite Carter's meddling, Reagan was eventually able to get a whole class of nuclear weapons abolished, and greatly reduced others.
Carter also sandbagged Clinton. Tapped to go to N Korea to see if there was a way to preserve peace and a non-nuclear Korea, Clinton found out by watching a CNN broadcast that Carter had greatly exceeded his authority and had a deal in hand that would avert war, keep the Kims in power in N Korea, pretty much ensure that N Korea got nukes, and would require the US to pay for it. Clinton was understandably furious.
Carter also sandbagged Clinton. Tapped to go to N Korea to see if there was a way to preserve peace and a non-nuclear Korea, Clinton found out by watching a CNN broadcast that Carter had greatly exceeded his authority and had a deal in hand that would avert war, keep the Kims in power in N Korea, pretty much ensure that N Korea got nukes, and would require the US to pay for it. Clinton was understandably furious.