John Wallace earned instant condemnation last month from Republicans after he picked the Democrats’ congressional map.

It wasn’t only because as chair of the state’s redistricting commission, he went with the Democrats. It was how he did it.

At the group’s ultimate Dec. 22 meeting, the former justice of the state Supreme Court said simply that he picked the Dems’ map because the Republican map was selected – by someone else – 10 years ago. So it was the Democrats’ turn this year.

Such reasoning was certainly a head-scratcher.

It didn’t take state Republicans very long to ask the state Supreme Court to review the work of their old colleague. The court responded by asking Wallace to further explain his thinking. That seemed pertinent, because Wallace didn’t do much explaining the first time around.

Now he has.

In a filing this week with the court, Wallace spoke of “partisan fairness” and “party blind.”

The first concept speaks to ensuring that the map reflects the current voting patterns of the state in terms of which party wins and loses.

The second test compares the proposed maps – ones drawn by both parties – to a theoretical map drawn automatically.

Wallace said in his court filing that the Democratic map was better on both counts.

He acknowledged that he should have said that, or something like that, on Dec. 22.

“I should have been more concerned with the fairness to the citizens of New Jersey,” Wallace wrote.

Many Republicans were suspect of Wallace from the get-go. So much so that Wallace said in his submission that the GOP chair – Doug Steinhardt – admitted doing background research on him (Wallace) and that he was satisfied with what he found.

That was presumably before Wallace made his decision.

Wallace also gave some info on the deliberation process, which culminated in a four-day stay at a Cherry Hill hotel.

He said it was “unfortunate” that the Republican and Democratic commission members did not share their proposed maps with each other.

That punctures any belief some may have had of commission members haggling long into the night over beer and pizza with both maps displayed before them.

And then he brought up another factor that he said tipped things in the Democrats’ favor.

Both sides obviously tried to sway Wallace.  To that end, he said the Dems’ presentation was superior, because it often referred to public testimony. He said Republicans relied more on their experts. There were 10 public hearings on the map – some live, some virtual.

The court will still consider the Republicans’ request to throw out the approved map. It’s doubtful if Wallace’s explanation satisfied the GOP.

However, the important question is whether it satisfied the court.