Hosting Rep. Paul Ryan on the Today show this week, Matt Lauer asked the Republican vice presidential candidate whether he would concede that some of the statements he made in his convention speech in Tampa last week “were not completely accurate.”

Specifically, Lauer pressed Ryan on his controversial assertion suggesting president Obama was responsible for the closing of a General Motors plant in Janesville, WI., when in fact GM made the plant-closing announcement in June 2008, while President Bush was still in office. (The plant halted its production of SUVs in December 2008; also while Bush was in office.)

Ryan's easily debunked attack on Obama has put the candidate on the defensive. It's also sparked a debate within the media about fact-checking and how to cover candidates who campaign while aggressively removed from the truth.

And yet despite the GM controversy, and through the endless debunking, Ryan has remained loyal to the issue, even tweeting about the plant closing this week:

Questioned by Lauer about the controversy, Ryan's told him to go “read the speech,” and then mounted this defense [emphasis added]

RYAN: What I was saying is, the president ought to be held to account for his broken promises. After our plant was shut down, he said that he would lead an effort to retool plants like the Janesville plant to get people back to work. It's still idle; people are still not working there.

But that's not what Ryan said in his speech last week.

In Tampa, Ryan quoted candidate Obama speaking at the auto plant on February 13, 2008, months before it was shut down. Then on Today, Ryan told Lauer he had referenced comments Obama made "after our plant was shut down." [emphasis added]

Hammered for dishonest comments he made in his convention speech about the closing of a GM plant, Ryan went on national television this week and compounded that dishonesty by revising what he said in his convention speech.

How is the press supposed to cover a post-truth politician like that? And should they trust Ryan's assertions in the future?

The first step for the press is to be diligent, which wasn't always the case while covering Ryan's plant-closing prevarications. As Bob Somerby noted at The Daily Howler, after Ryan appeared on Today, the show's website posted a report that promptly botched a key fact:

During his acceptance speech last week at the Republican National Convention, Ryan made a reference to a campaign visit that then-presidential candidate Obama made to a GM plant in Janesville, Wis. However, the plant had already been shut down when Obama paid the visit.

False. The plant had not been shut down when Obama visited in 2008, and claiming it had been completely confuses the issue of Ryan's remarks.

By contrast, the Boston Globe did a much better job holding Ryan accountable and pointing out his new explanation was at odds with what he actually said in his Tampa speech:

But in his speech, Ryan knocked Obama for statements he made before being elected president and before the plant shut down. He did not mention anything Obama said as president about getting people back to work after the plant closed.

Ryan's continued mishandling of the GM plant-closing story ought to signal to the press that it needs to treat the candidate's future claims with care.