The Supreme Court has agreed to take up a case that could derail hundreds of Jan. 6 felony prosecutions — and could also deal a blow to special counsel Jack Smith’s prosecution of former President Donald Trump.

The case, arising from the prosecution of a Jan. 6 defendant accused of pushing against police and inflaming a mob attempting to breach the Capitol, calls into question prosecutors’ handling of an Enron-era obstruction law to punish those who stormed Congress.

The charge, “obstruction of an official proceeding,” carries a 20-year maximum sentence and is one of the felony counts that Trump is facing in his own Washington, D.C. criminal case.