A decision by the US supreme court to take a case linked to the January 6 attack on the Capitol could have consequences altering the trajectory of the criminal case against Donald Trump over his effort to overturn the 2020 election as well as for hundreds of other people prosecuted for the riot.

The nation’s highest court has agreed to consider whether federal prosecutors can charge January 6 riot defendants with a statute that makes it a crime to obstruct an official proceeding of Congress – a charge also filed against Trump in his 2020 election-interference case.

The decision by the conservative-dominated court to take up the matter complicates and could delay Trump’s trial in federal district court in Washington, which is currently scheduled for next March.

The supreme court’s eventual ruling in Fischer v United States will indicate whether the obstruction charge under section 1512 of title 18 of the US criminal code can be used against Trump, and could undercut the other general conspiracy charges brought against the former president by the special counsel, Jack Smith.

The court could also end up by extension invalidating many convictions against rioters involved in the January 6 Capitol attack. The obstruction statute has been the justice department’s primary weapon to hold accountable those involved in the violence of that day.

The case involves Joseph Fischer, who was indicted in Washington on seven counts of obstructing the congressional certification of the 2020 election results when he assaulted police officers during the riot.

Fischer sought to dismiss part of his indictment, arguing that the obstruction statute passed under the Sarbanes-Oxley Act of 2002 in response to the Enron scandal, had to do with document or evidence tampering for white-collar financial crime.

The US district judge Carl Nichols, who presided in the case, interpreted the statute as requiring prosecutors to show that the defendant took some action with respect to a document or record and did not apply to Fischer as he assaulted police officers at the Capitol.

But a split three-judge panel at the US court of appeals for the DC circuit reversed the decision, deciding that obstruction applied more broadly and encompassed impeding any official proceeding. Fischer, and two other January 6 defendants, appealed to the supreme court to resolve the issue.

The supreme court may not decide whether the obstruction statute can be applied to the Capitol attack until June, when the next term ends. In the meantime, the viability of that charge – and potentially that of other general conspiracy charges – against Trump remains uncertain.

It could also give Trump an opening to seek to pause ongoing pre-trial proceedings in his 2020 election interference case pending the supreme court’s consideration of the issue, although he is unlikely to succeed and it may not be appealable should such an effort be denied.

Similar criminal cases involving members of Congress or congressional aides, for instance, typically go to trial and are then tried again if a higher court finds that some of the charges were inapplicable.

At issue for Trump is the definition of “corruptly” in the obstruction statute. The DC circuit has been unable to agree, with judge Justin Walker interpreting it as “unlawful benefit”, while judge Greg Katsas interpreted it as “an unlawful financial, professional, or exculpatory advantage”.

The obstruction statute was never a natural fit for January 6 cases, and defense lawyers have repeatedly argued in trial and appeals courts in Washington that the justice department was using it in an overly broad fashion to target rioters because of the 20-year maximum sentence it carries.

The problem for the justice department now is that the supreme court has previously chafed at the use of broad conspiracy arguments by federal prosecutors.

In the case of Jeffrey Skilling in the Enron scandal, the court held in a unanimous decision that Skilling had been improperly charged with the “honest services” provision of the statute about a scheme to defraud, because it applied only to accepting bribes and kickbacks.

“The court’s been very clear that over-aggressive theories under general criminal statutes don’t fly,” said the former House general counsel Stanley Brand, whose firm Brand Woodward has also represented January 6 defendants. “That’s the lesson of Skilling and all these other cases.”

If the supreme court were to rule in favor of Fischer next year on the basis that the justice department was using charges that were too broad, Brand added, it could undercut the other general conspiracy statutes used in the indictment against Trump, as well.