The Weekly Standard‘s John McCormack offers a step-by-step account of the war of words between Nobel Prize-winning economist Paul Krugman and U.S. Rep. Paul Ryan, R-Wis.

The latest development? The voluble Krugman’s now deafening silence.

On Sunday,
Krugman continued to level his accusation of bad faith against Ryan,
writing that “Ryan could have gotten JCT to do a 10-year estimate; it
just wouldn?t go beyond that. And he chose not to get that 10-year
estimate. So it was Ryan?s choice not to have any independent estimate
of the 10-year revenue effects.” Krugman also criticized Ryan for not
defending his proposed spending freeze.

On Monday,
Ryan told THE WEEKLY STANDARD that Krugman’s claim is just not true–he
did ask the JCT to do a 10-year estimate, but it was too busy to
perform the task. (So Ryan asked Treasury Department experts to look at
the plan, and they said the numbers added up.) In his TWS interview, Ryan disputed Krugman’s claims that his proposed spending freeze is impractical and that the Roadmap
would raise taxes. Ryan said Krugman’s attack was “intellectually lazy”
and “ad hominem.”

On Tuesday, Krugman wrote a blog post merely claiming that his criticism of Ryan was not ad hominem. Krugman had previously attacked Ryan personally as an “unscrupulous flimflammer” and “charlatan” who exudes the “audacity of dopes.” Merriam-Webster’s dictionary defines “ad hominem” as “marked by or being an attack on an opponent’s character rather than by an answer to the contentions made” (“ad hominem” also has a technical meaning in the realm of logic, as the Wall Street Journal‘s James Taranto points out).

Much more remarkable than Krugman’s quibbling over the definition of “ad hominem” is his silence on whether he was wrong to have falsely claimed that Ryan chose not to have JCT score the Roadmap. As The Atlantic‘s Megan McArdle wrote later in the day on Tuesday: “Paul Krugman is Still Wrong on Paul Ryan and the CBO.”