He Shall, From Time to Time...
There is no law that requires the President of the United States to appear before a full congress, nor to do so annually, biannually or once a term.
The Constitution simply states that the President “shall from time to time, give to the Congress Information of the State of the Union.” That's it. Nothing more is said about it. In fact, because there is no law even requiring the President to walk into Congress to give an address, Congress is also not required to make accommodation to the President. Therefore, the President must be invited.
It's an interesting little tidbit, for the illustration of how it's often the case that tradition is a more natural, even more universal thing than law. Traditions—maybe because of built-in restrictions or maybe because they exist solely by fiat—tend to be immune to the interpretational whim of a changing culture.
Interesting then, that most political organizations these days—and by political organizations, I include corporations (politics of greed), governments (politics of society) and even religions (politics of the soul)—tend to drive any situation towards the letter of law, seemingly in order to remove interpretability.
But law will always be subject to interpretation, and traditions supposedly not. Look and see how the conservatives, who are supposed to be in favor of the smallest government possible, has no problem passing law after law that grows and grows the government to provide an umbrella over their supposedly strong morals, strong faith.
The strict father of government gets a bigger belt, a longer arm, a more powerful fist and far better eyesight. The Fatherland gets to take the locks off the children's doors, to chase after women who insist on the right to choose, to slap down weakness, where weakness is defined by Bubba America.
It's never strong to discuss, instead to dictate; never strong to recognize nuance, instead to broadside with simplistic pablum; never Athens, only Sparta.
Tradition isn't supposed to be fucked with; moralists always rely on tradition. Morals are relative, morals are subject to Time, morals are a personal matter. Say this to the intravenous aphorism junkies who mainline Rush Limbaugh or Ann Coulter or Sean Hannity, and you'll be called a Liberal or a Traitor or you'll just have your mike cut off.
These are people with no respect for law, only tradition, even as they deconstruct tradition to suit their Ascendancy.