Tim Kaine claims he would have easily been reelected if he would have been able to run in November. While Kaine has had his moments of popularity in this state, he's been on a downward slide since his handling of the aftermath of the Virginia Tech shootings.
Kaine failed to live up to the promises he made to the left of the Democratic Party, and found ways to draw the ire of the state GOP. He squandered the budget and failed to get anything substantial moving on transportation. He would not have been able to rally the independents like he did in 2005, as they had grown disenchanted with both him and the Democrats.
Would Kaine have lost by the same margin as Deeds? Probably not, as he had name recognition. However, Kaine would have lost by 6-8 percent. I'm pretty sure of that. Timmy's got an awful high opinion of himself to make such a bold statement.