Exodus 13:10 says that Pesach shall be observed "mi-yamim yamimah", literally "from days to days". But this has been understood to mean "from year to year", and thus we have Pesach once a year.
The early interpreters of the U.S. Constitution must have been familiar with rabbinic exegesis. Article II says that the President "shall from time to time give to the Congress Information of the State of the Union, and recommend to their Consideration such Measures as he shall judge necessary and expedient." The text specifies nothing about the frequency of this presidential requirement, nor have there (to my knowledge) been any legislation or Supreme Court decisions refining this clause. However, the Constitution shebe-'al peh has always understood the State of the Union address (whether in person or in writing) to be an annual obligation, interpreting "from time to time" to mean "from year to year". This is halachah le-Moshe mi-Sinai.
King George's sixth (and antepenultimate!) State of the Union Address will be this Tuesday night. Before it starts, be sure to take the State of the Union Predictions Quiz, and prognosticate everything from the color of his tie to the presence of purple fingers. During the address, play the State of the Union Drinking Game! I'll be playing a non-alcoholic version and getting trashed on Leo's. All are invited over here.