An escalating partisan clash in Ohio threatens to bar US President Joe Biden from the state's ballot in the November election.
The state's top election official said earlier this week that he may begin preparing ballots for the presidential election that do not include Mr Biden's name.
He warned that Democrats are nominating their candidate too late to comply with ballot access laws in Ohio.
Such conflicts have been quietly resolved in the past - but the Biden campaign may be forced to sue to get on the ballot.
Ohio requires political parties to officially confirm presidential and vice-presidential nominees to the elections chief, 90 or more days before the general election.
That means Mr Biden and Kamala Harris, his vice president, must be certified as the Democratic candidates by 7 August.
Though Mr Biden has secured the votes necessary for the Democratic nomination, he will not be named formally as the party's candidate until the nominating convention this summer.
But the Democratic National Convention is from 19 to 22 August.
"The conflict between the August 7, 2024 certification deadline and the date of your party's nominating convention is well established," Ohio elections chief, Secretary of State Frank LaRose, wrote in a Tuesday letter to Ohio Democratic Party leadership.
"Unless your party plans to comply with the statutory deadline, I am duty-bound to instruct boards of elections to begin preparing ballots that do not include the Democratic Party's nominees for president and vice president of the United States," the Republican said.
Former President Donald Trump, the presumptive Republican candidate, will not face the same issue. His party's national convention is 15 to 18 July, well in advance of the Ohio deadline.
But party conventions, both Democrat and Republican, typically are held in the summer before a presidential contest - and similar issues with certification deadlines are rectified with little drama.
Earlier this year, Democrats in Washington state and Republicans in Alabama made provisional changes necessary to exempt Mr Biden from ballot deadlines.
Ohio itself has done the same in the past, with its Legislature making exceptions for Mitt Romney, the Republican presidential nominee in 2012, and Mr Trump in 2020.
The state's governor, Mike DeWine, called on lawmakers to act in a similar vein. Mr DeWine is a moderate Republican who has distanced himself from the party's Trump-friendly wing.
But the state's Republican House speaker said the body would not make a legislative fix to the issue.
"There's just not the will do that from the Legislature," Speaker Jason Stephens told reporters on Tuesday.
The Biden campaign is continuing to express confidence the issue will be resolved without drama.
“Joe Biden will be on the ballot in all 50 states,” Charles Lutvak, a campaign spokesperson, told US media.
“Election after election, states across the country have acted in line with the bipartisan consensus and taken the necessary steps to ensure the presidential nominees from both parties will be on the ballot.”
But with a legislative remedy by state Republicans off the table, the sitting US president may have to seek legal action.
Ohio, once viewed as a swing state, has become increasingly conservative. Mr Trump won Ohio in both 2016 and 2020, defeating Hillary Clinton and Mr Biden by roughly 8% margins both times.
The fight over Ohio's ballot comes after another partisan clash earlier this year - one that threatened Mr Trump's ballot appearance.
Officials in Colorado, Illinois and Maine ruled that the Republican was barred from returning to the White House under a Civil War-era insurrection clause in the US Constitution.
The US Supreme Court ultimately knocked down that decision in March, ruling that Mr Trump must be placed on the three states' presidential ballots.
