What principle have presidents applied to keep white house communications confidential?

The Executive Privilege

Explanation:

The Executive Privilege is the power of the Executive branch to withhold information from other government branches in order to preserve confidential communications within the executive branch or to secure the national interest, that is to say, the Executive's power to decide what to share.

Richard Nixon, for example, was one of the Presidents that applied it when he was accused of being involved in the Watergate Scandal, however, in the case, the Supreme Court established that the executive privilege had limits and it wasn't immune from judicial review and from the demands of due process of law.

the federal government of the united states was established by the constitution. us is a presidential republic. the president is head of state, head of government and of a two party legislative and electoral system. the supreme court balances the powers of the federal and the state government. yhe executive branch is headed by the oresident. there are two chambers of congress, the senate and the house of representatives. judicial power is exercised by the judicial branch (or judiciary), comprised of the supreme court and lower federal courts. the judiciary's function is to interpret the   constitution as well as the federal laws and regulations.

answer; /// all of the above;