While there is an act that President Trump and his supporters are citing, titled the Presidential Records Act (PRA), to accuse House Speaker Pelosi of breaking federal law, it is important to understand what actions the law accounts for. The act mandates that the President of the United States preserve records and other laws governing the federal government. This serves as a form of checks and balances to prevent the president and his advisers from shielding documentary information from public view. The act is fairly new, as it was passed in 1981.
It is important to realize that this law does not apply to print outs or widely circulated documents. Moreover, the copy of the State of the Union that she was given is not a governmental record. Therefore, House Speaker Pelosi did not violate the Presidential Records Act, nor any other federal law.
However, it is open to debate whether Pelosi's action was appropriate, though I will not commentsupply my opinion on that matter.