Conventions are designed primarily to boost the presidential candidate, not individual speakers, said Democratic former congressman Kweisi Mfume.
"The focus should be on the nominee and the vice presidential nominee — you really downplay yourself," said Mfume, who spoke at the 2004 convention and is a delegate for Obama next week. "You want to deliver with sincerity, you want to have some authority, you want to have some humor and you want to downplay yourself."
Obama might present the most powerful example of the potential a convention speaking slot offers for political advancement. A candidate for the Senate in 2004, he used his keynote address to introduce himself to a divided nation as a figure of conciliation.
"There's not a liberal America and a conservative America," he told the delegates in Boston. "There's the United States of America."
The widely cited speech didn't get Democratic nominee John Kerry elected president in 2004, but it established the political persona that would help Obama win the White House four years later.
At the same convention, O'Malley gave an address remembered, if at all, as a high-flown misfire.
"America the beautiful, whose alabaster cities gleam undimmed by human tears," the then-mayor of Baltimore said in one of its most notorious passages. "Oh, my friends, to govern is to choose."
"There was a lot of grandiloquence," said Richard Vatz, a professor of rhetoric at Towson University. "It looked like a young guy lacking confidence who was trying to be profound. And that kind of rubs a lot of old heads the wrong way."
Vatz says O'Malley is unlikely to fall into the same trap again. After two statewide elections and six years as governor, he said, O'Malley "is going to feel as if he belongs more."
About 22 million viewers tuned in to watch addresses by former secretary of state Condoleezza Rice and vice presidential nominee Paul Ryan during this past week's Republican convention. That was down from more than 37 million who watched in 2008, when Sarah Palin was the party's pick for vice president.
Put another way, convention speeches are increasingly targeted at party insiders and pundits as much as they are voters, most of whom are still sorting out their choice for 2012, let alone 2016.
"We'll all be evaluating him every time he takes a breath for the next four years," said Stuart Rothenberg, another respected Washington-based political analyst. "It's an opportunity, and if you're Martin O'Malley you want to take every opportunity to make a good impression, to be smart and interesting, and show some charisma."
Donald F. Norris, who chairs the public policy department at the University of Maryland, Baltimore County, sees only upside for the governor.
"This is a huge opportunity for O'Malley, and clearly it has come in recognition of his rising star within the party," he said. "My guess is nothing but good can come from this for his political career."
Rep. C.A. Dutch Ruppersberger says O'Malley will be ready.
"Martin's a phenomenal speaker," said the Baltimore County Democrat, who will head to Charlotte this week. "He'll do our state proud."