The White House has gradually but dramatically altered its account of how domestic violence accusations against former staff secretary Rob Porter were handled internally.

Last Wednesday, the day after the Daily Mail reported claims of abuse by both of Porter's ex-wives, White House press secretary Sarah Huckabee Sanders indicated that the administration was in no hurry to push Porter out the door. Sanders said that Porter “is going to be leaving the White House . . . but is going to stay on to ensure that there's a smooth transition.”

She added that resigning “was a personal decision that Rob made and one that he was not pressured to do.”

On Thursday, deputy White House press secretary Raj Shah said twice during a media briefing that Porter had been “terminated.” Shah seemed to be trying to suggest that Porter had been forced out, but later said, “I just mean the process by which your employment status ends is termination.”

On Monday, another deputy press secretary, Hogan Gidley, went further.

“As soon as we found out about this on Tuesday, by Wednesday Rob Porter was gone,” Gidley said on “Fox & Friends.”

From a lack of urgency to swift action, the White House can't get its story straight. And this is just what spokesmen have said on the record. Granted anonymity in some news reports, administration officials have offered conflicting versions of events that range from White House Chief of Staff John F. Kelly demanding Porter's resignation to Kelly urging Porter to stay on the job and fight the allegations.

Washington Post White House bureau chief Philip Rucker observed Sunday that the White House “still doesn't have a consistent timeline of events,” to which colleague Mark Berman responded with a question: “What happens when there's an external crisis and the White House needs the American people to believe what it says?”

This is why the White House's inconsistencies on Porter matter, in the big picture. There are moments when government officials serve as reporters, of sorts, because they are the first or only ones to possess vital information. But they can only serve effectively if their credibility is intact.

Last year's shooting at a Republican practice for the Congressional Baseball Game provided a good example. Here's what I wrote at the time:

When a gunman opened fire Wednesday at a Virginia baseball field where Republican members of Congress were practicing for a charity game, TV trucks sped to the scene to broadcast live reports from their journalists. That's how breaking news coverage typically unfolds.

But the first people in position to report on the shooting were the members themselves. In the immediate aftermath, several congressmen took the role of journalists, calling in to cable news stations to describe what happened, before cameras and network correspondents arrived.

“In this case, the lawmakers are the best reporters,” “Fox & Friends” host Brian Kilmeade said while speaking with Rep. Jim Jordan (R-Ohio).

Kilmeade was right. The public counted on lawmakers to accurately describe the shooting as it had unfolded. The best evidence that they were accurate is that they did not contradict one another.

In Trump's White House, contradictions abound — and not only in the Porter episode. Recall that when Trump fired James B. Comey as FBI director, his spokesmen initially said he had acted on the recommendation of Deputy Attorney General Rod J. Rosenstein. The president then told NBC that he had resolved to fire Comey “regardless of recommendation.”

Remember the time The Post reported that Trump had shared classified information with Russian diplomats during a meeting in the Oval Office? Two national security advisers called the story “false” before Trump tacitly acknowledged that it was true by tweeting that he had the “absolute right” to share the information.

The Trump White House routinely fails to establish whether and when key events happened. At some point, it might wish it could provide a ticktock that the media and the public would accept at face value.