Former president barred from appearing on Republican presidential primary ballot over his role in US Capitol attack.

Cook County Circuit Judge Tracie Porter, however, delayed her ruling, issued on Wednesday, from taking effect in light of an expected appeal by Trump.

In her ruling, Porter sided with Illinois voters who argued that the former president should be disqualified from the state’s March 19 primary ballot and its November 5 general election ballot for violating the anti-insurrection clause of the US Constitution’s 14th Amendment.

The final outcome of the Illinois case and similar challenges will likely be decided by the US Supreme Court, which heard arguments related to Trump’s ballot eligibility on February 8.

Porter said she was staying her decision because she expected his appeal to Illinois’s appellate courts and a potential ruling from the US Supreme Court.

The advocacy group Free Speech For People, which spearheaded the Illinois disqualification effort, praised the ruling as a “historic victory” in a statement.

A campaign spokesperson for Trump, the national frontrunner for the 2024 Republican nomination, said in a statement this “is an unconstitutional ruling that we will quickly appeal”.

Colorado and Maine earlier removed Trump from their state ballots after determining he is disqualified under Section 3 of the 14th Amendment to the Constitution.

Both decisions are on hold while Trump appeals.

Section 3 bars from public office anyone who took an oath to support the US Constitution and then has “engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof”.

Trump supporters on January 6, 2021, attacked police and swarmed the Capitol in a bid to prevent Congress from certifying Democrat Joe Biden’s 2020 election victory. Trump gave an incendiary speech to supporters beforehand, telling them to go to the Capitol and “fight like hell”. He then for hours did not act on requests that he urge the mob to stop.

The Supreme Court is currently weighing Trump’s challenge to his Colorado disqualification.

The justices in Washington appeared sceptical of the decision during oral arguments in the case, expressing concerns about states taking sweeping actions that could affect the national election.