He can't. Obfuscate, impute things neither said nor implied, straw men, and change subject.
That's just for starters.
The answer is that TB believes the Iranians should just forgive and forget, let bygones be bygones. The CIA and SAVAK were just efforts to create a school-lunch program for Iranian kids that got a little out of hand.
One may as well try to reason with a "Tickle Me Elmo", or talk to the Oracle at Disneyland as get a sensible answer from a True Believer. When they can't spin, they just talk about something else, fingers in their ears, ignoring reality until the Rush Limbaugh show comes on the air to revitalize their irrationality.
They can turn up the volume very high, and take their fingers out of their ears safely. Now, if Rush says it and a blog repeats Rush, that's as good as the Bible.
Arf