Is is legal to tape the president without his knowledge?

Omarosa Manigault Newman released a recording that she says is of a phone call she had with President Trump the day after White House Chief of Staff John Kelly fired her. This comes after Omarosa released a recording Sunday of her own firing from inside Situation Room, which is the most secure room in the White House. President Trump fired back on Twitter, calling her a “loser” and “vicious, but not smart.” Others in the White House say the recording is illegal and a threat to national security.