The retiring lawmaker acted as Mandel's opponent, Sen. Sherrod Brown (D-Ohio), in debate prep, and he said that's when he realized there was a problem.
"We got to a question on Asian Carp, and his answer was, 'It is Barack Obama's fault that we have the Asian Carp problem,' " LaTourette told the Cleveland Plain Dealer.
Mandel challenged Brown in one of the nation's most expensive contests, and lost by 5 percentage points.
The influx of outside money brought condemnation from Democrats, and Brown's campaign often cited a $30 million figure in spending from outside GOP groups to take him down. LaTourette acknowledged that Mandel's loss was "not a question of money," because "Josh Mandel had more money than God," he said.
The Senate candidates in Ohio were largely dependent upon the top of their ticket, and if Mitt Romney had been able to pull out a win there, Mandel might've found himself at orientation sessions last week.
But he also made a number of missteps — earning himself the "Pants on Fire" crown for the number of statements he made that were deemed false by the Cleveland Plain Dealer — that didn't boost his chances.
LaTourette acknowledged that Mandel would've had to outrun Romney in the state, and said that "he had been told to fight everything," which he said was poor guidance from his advisers.
"It's a question of, he needed Mitt Romney to carry Ohio by 8 to beat Sherrod, and whoever was giving him advice really should have been fired because it was bad advice."