Here’s a political battle line we didn’t anticipate. Maybe it’s not so political as it is ideological — which might be an exception in Pennsylvania.

Philadelphia District Attorney Seth Williams stridently disagrees with Gov. Tom Wolf’s moratorium on the death penalty. Williams filed a lawsuit with the state Supreme Court on Wednesday, five days after Wolf said he would issue reprieves at least until he receives a report from a legislative commission that has been studying the issue since 2011.

To political observers, the dust-up developing between governor and prosecutor could become significant. Both are Democrats. And with Pennsylvania Attorney General Kathleen Kane mired in controversy and under investigation for grand jury leaks, Williams might be considered Pennsylvania’s most prominent untarnished prosecutor.

The case raised in Williams’ filing involves Terrance Williams, who was convicted of the 1984 robbing and fatal tire-iron beating of another man. Since then, his death sentence has been fought in state and federal courts.

Terrance Williams’ execution had been scheduled for March 4, but Pennsylvania death row inmates have routinely been able to win delays, with the state’s last execution carried out in 1999.

There’s no reason to believe Terrance Williams would not have won another delay of his March 4 execution — that would have been business as usual. But Wolf’s declaration of a moratorium negates any reason for Williams to seek a reprieve — for now. The governor has already given it to him.

Seth Williams’ lawsuit changes the stakes, however. It puts the onus on the governor to justify an action he probably did not have to take, and now Wolf must prove he exercised a legitimate executive power.

That’s no slam dunk. A weekend editorial in the Lebanaon Daily News emphasized: “Wolf has circumvented a standing law of Pennsylvania, stretching the executive power of his office beyond that of both existing legislation and judicial decisions made over which he should have no say.”

Uncertainty has evolved into the primary argument against capital punishment. Modern science, specifically the DNA test, has proved the innocence of some death-row inmates both here and in other states.

But opponents of the death penalty need to note the irony of their argument — that DNA testing can just as accurately remove all doubt of a convict’s guilt, thus negating their primary argument against justified executions.

By declaring a moratorium, Gov. Wolf attempted to circumvent the criminal justice system along with state and federal law. Seth Williams’ lawsuit pulls the issue back into court, where it belongs.

Wolf professes to be an agent of open government. He should, therefore, have little trouble defending his opinion there.