Okay, I'm succumbing to the urge to get my two cents in on Chris Christie.
What this bridge embarrassment reminds me of is the resignation of Nixon. After that happened, some European friends of mine expressed their incredulity that such a seemingly small thing (compared, say, to Reagan's Iran-Contra treason) could result in driving a President from office. What they didn't understand was this: There were always two views of Nixon in the country- Nixon, the brilliant politician and master statesman who could guide the country through any crisis, and Nixon-well not to mince words- the crook. What Watergate did was make it impossible for most people to believe in the first alternative. Watergate played right into the most negative stereotypes about Nixon.
Well, that is the reason that this bridge scandal is going to do so much damage to Christie. There is already a well-established narrative of Christie as a belligerent bully, and this incident plays right into it. In fact, in my lifetime, I've seen almost all political "scandals" that did real damage to people work for exactly that reason- it just made it too believable that they were what their opponents said they were.
Not that it will affect Christie's chance for the nomination- after all, he's in a party that just welcomed back to the Congress a guy busted with three and a half grams of coke. But with people who admit they are Republicans now down to 25% in a recent poll, getting the Republican nomination is likely to prove a quick route to oblivion.