TAMPA – It’s become a ritual at party conventions to feature an endorsement speech from a politician who was once a member of the opposing party. Tonight, that task fell to former Democratic representative from Alabama, Artur Davis, who gave a strong version of this genre of political speech.

In a stinging address, Davis spoke to the voters such as himself who had high hopes for President Obama when they voted for him in 2008, but have since been disappointed. This is an argument that resonates with the type of voter who may understand that Obama inherited a tough situation when he took office, but still think he came up far short of his promise four years ago, when he vowed to usher in a new era in American politics.

Davis said:

But in all seriousness, do you know why so many of us believed? We led with our hearts and our dreams that we could be more inclusive than America had ever been, and no candidate had ever spoken so beautifully.

But dreams meet daybreak: the jobless know what I mean, so do the families who wonder how this Administration could wreck a recovery for three years and counting.

So many of those high-flown words have faded.

Remember the President saying of negative politics and untrue ads, “not this time?”

Who knew “not this time” just meant “not unless the economy is still stuck and we can’t run on our record?”

Remember, too, when he said, “this was the moment when the rise of the oceans began to slow and our planet began to heal?”

Who knew the plain English version of it was, “middle America, get ready to shell out 60 bucks to fill up your car?”

And in terms of their crown jewel legislative achievement: who knew that when asked, “will government impose a new federal mandate requiring middle class Americans to buy health insurance whether they can afford it or not?”

The answer would be “Yes we can!”

His speech concluded by declaring, “May it be said of this time in our history: 2008 to 2011: lesson learned. 2012: mistake corrected.”

It’s hard to see Charlie Crist, the former Republican governor of Florida, topping that when he speaks next week at the Democratic convention in Charlotte to endorse Obama.