President Donald Trump on Monday tweeted that he has the "absolute right" to pardon himself, but the Department of Justice's website says otherwise.

"Under the fundamental rule that no one may be a judge in his own case, the President cannot pardon himself," the website states.

Trump has already issued a number of pardons in his first 500 days as president, including to controversial individuals such as former Arizona sheriff Joe Arpaio.

President Donald Trump on Monday tweeted that he has the "absolute right" to pardon himself, but the Department of Justice's website says otherwise.

Trump tweeted, "As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong? In the meantime, the never ending Witch Hunt, led by 13 very Angry and Conflicted Democrats (& others) continues into the mid-terms!"

The president was seemingly suggesting he could take steps to protect himself from special counsel Robert Mueller's investigation into Russian election interference and the Trump campaign's possible role in it.

But the Department of Justice's website clearly states, "Under the fundamental rule that no one may be a judge in his own case, the President cannot pardon himself."

This is based off a decision made on August 5, 1974, shortly before President Richard Nixon resigned amid the Watergate scandal.

The decision also states that if the president "declared that he was temporarily unable to perform the duties of the office" under the 25th Amendment, technically the vice president could pardon him after becoming acting president.

"Thereafter the President could either resign or resume the duties of his office," the decision states.

Additionally, the decision notes "it could be argued" that Congress could issue a pardon for the president, even though the Constitution states the power rests exclusively with the president, because doing so "would not interfere with the President’s pardoning power because that power does not extend to the President himself."

In other words, since the president cannot pardon himself, it would not necessarily be unconstitutional for Congress to do so because it wouldn't undermine his or her authority in this regard, but this is hazy legal territory.

The president's authority to pardon people is outlined in Article II, Section 2 of the Constitution. Since the time of George Washington, presidents have used the pardon power as a means of forgiving certain people who have been convicted or accused of various crimes.

Trump has already issued a number of pardons in his first 500 days as president, including to controversial people such as former Arizona sheriff Joe Arpaio and more recently conservative author and filmmaker Dinesh D’Souza.