In the courtroom, New Jersey’s experts testified that Exxon was responsible for $8.9 billion in damages to the state’s natural resources, primarily through the destruction of creeks, wetlands and aquatic life. Exxon swung away at the state’s case during trial but never landed a punch, as I saw firsthand as one of the witnesses called by Exxon to testify. The presiding judge — an admired expert in environmental law who had been recalled from retirement for the trial — had been expected to issue his decision soon.

But sometime during the judge’s deliberations, the Christie administration asked him to defer his ruling.

One would think that Mr. Christie would have kept his immediate political staff at a distance from these negotiations.

While he was chairman of the Republican Governors Association in 2014, the group received $500,000 from Exxon and more from company employees. While this was not Exxon’s first contribution to the group, this donation was made at a time when the New Jersey trial was pending.

If nothing else, the optics, as they say in politics, look bad. Had the governor or his staff stayed away from the case, they would have avoided the obvious and unseemly inference that the settlement had something to do with the contribution.

All settlements involve compromise, of course. But Governor Christie left billions on the table, if the testimony of the state’s own experts is to be believed. This would be true even if the judge, who must still approve the settlement, were to reduce the experts’ figure by 50 percent or more.

The administration has so far refused to release the text of the agreement. One worry is whether it also releases Exxon from liability at other polluted New Jersey sites that were not part of the case and where damage has not been assessed. If so, the value to Exxon of the deal could exceed the $8.9 billion by several hundreds of millions of dollars.