The pro-choice referendum seemed poised to win in the conservative state of Ohio in November. In response, Republican state legislators are accused of shifting the goalposts.

Michael Curtin has been umpiring high school and college baseball games throughout central Ohio for 22 years, just like every summer.

The retired journalist, who spent 38 years in journalism before moving into state politics, loves the game. This summer, Mr Curtin neglected his umpire equipment, keeping it in the basement of his Columbus home so he could focus on Ohio politics instead.

It’s not just one game for me,” he said. The fight is too important for me to lose.

There is a battle brewing over Issue 1, an otherwise dull and procedural referendum on the minimum threshold for constitutional amendments.

In simple terms, voters will decide whether to maintain the 50% plus one threshold or raise it to 60% on 8 August.

Yet Ohio’s vote has become a proxy war over abortion, one of many state-wide battles that have broken out since the Supreme Court rescinded abortion rights nationwide last June.

The reason is that Issue 1 is not the only referendum looming over the horizon. Ohioans will vote in November on another constitutional amendment that would protect abortion access until foetal viability, around 24 weeks of pregnancy.

It is claimed by proponents of issue 1 that Tuesday’s vote is simply intended to protect the state constitution.

But its opponents, including Mr Curtin, a retired Supreme Court judge and all of Ohio’s living former governors, have called foul. A backhanded attempt to change the rules mid-game, raising the voter threshold just in time to thwart the abortion vote, is what they claim Issue 1 is.

Everyone knows what’s going on here,” Mr Curtin said. In my opinion, this was just bad faith.”

The country’s abortion fight has increasingly played out on state ballot initiatives since Roe v Wade was overturned last June. As of now, there have been six victories for abortion rights.

In Ohio, if the vote passes, it will be the most comprehensive affirmation of reproductive rights in a state dominated by Republicans, said Mary Ziegler, a law professor at the University of California, Davis and an authority on abortion in the US. There will be some sort of consensus regarding abortion rights, even in conservative states.”

Recent surveys indicate that all Ohioans would vote in favor of abortion if they went to the polls now. In a July poll conducted by USA Today and Suffolk University, 58% of Ohioans support the constitutional amendment, while 32% oppose it.

If Issue 1 passes first, and the threshold is raised to 60%, the abortion rights amendment may be passed.

Pro-Choice Ohio executive director Kellie Copeland says the anti-abortion movement clearly saw that they could not win without changing the rules.

A full-throated support for Issue 1 has been provided by Ohio’s secretary of state, Frank LaRose.