Presidents are not vetted for being security risks. Their election is considered the will of the people.
Presidents deal with national security every day starting with morning briefings, and going to bed with the latest current info and maybe being awakened during the night for actions like maybe scrambling jets to support embassies like Benghazi which was not done. The president is the commander in chief of the armed forces and falls under both military and DoD regulations concerning troop actions and logistics. He/she is responsible for all his/her actions concerning military matters to include sensitive information. This is why the president can be tried, found guilty, and sentenced for high crimes like murder and treason even though the president is still in office. He/she cannot use presidential privilege for crimes like this. It falls under COMSEC, and is a crime to knowingly violate security parameters established for protection of life and limb.
All persons working for the government that have access to the world wide, therefore, matters of security can be found guilty of breach, including the president. The only difference from being hired or elected to do a job for the government is who decides. Same animal, same laws/regulations.
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