A president falsely charging "treason" is what the Founders feared

In 18th-century England, royal accusations of treason were “a means of suppressing political dissent and punishing political opponents for crimes as trivial as contemplating a king’s future death (what was known as ‘compassing’), or speaking ill of the king (‘lèse majesté’),” the University of Texas law professor Steve Vladeck wrote. “King Henry VIII even had two of his six wives executed for alleged adultery on the ground that such infidelity was, of itself, ‘treason.’”…

The Framers were guarding against the possibility that Americans would one day elect a man so morally weak and corrupt that he would falsely accuse political enemies of treason. In 2016, Americans narrowly elected a man who is that degraded. Congress and the judiciary have a constitutional duty to check his abuses of power, and the public has a patriotic duty to oust him from office. But as yet, most Republicans show no inclination to mount a 2020 primary challenge, as if they are content to continue supporting a man of low character.

Their failure, while disconcerting, is not treason, as it is neither levying war against the United States nor adhering to its enemies nor giving them aid and comfort.