DENVER — Sen. Barack Obama (D-Ill.) is tightening the reins on campaign speeches and stressing that speakers emphasize a rags-to-riches theme.

Members of Congress and others who have been asked to address the convention must have their speeches approved by the Obama campaign. In many cases, the speeches are drastically changed — to the point where the original speech is completely scrapped, Democratic sources say.

Still, the practice of making wholesale changes to speeches has some Democrats miffed. “This is politics through and through,” said a Democratic source who has seen firsthand the degree to which the Obama camp has changed some of the speeches of members of Congress. “Everyone gets vetted.”

Obama has made one exception, however. He recently said he will not edit the speech of former President Bill Clinton.

The Democratic source expressed dismay as to why nearly everyone delivering speeches on behalf of Obama has to have a rags-to-riches story, dredging him- or herself up out of poverty and into prosperity. The source conceded, though, that it is Obama’s convention and he has a right to do as he pleases.

Yet not every speech has been completely overhauled. Rep. Dennis Kucinich (D-Ohio), who was asked by Obama to speak about the economy, was scheduled to deliver his speech Tuesday afternoon. The Obama campaign struck just one line from his speech, which slammed the Republicans and the Bush administration, according to a Democratic source.

That line, addressing Republicans, read: “They’re asking for another four years — in a just world, they’d get 10 to 20.”

Democratic strategist James Carville believes the Obama campaign is pulling its punches.

Speaking on CNN, Carville said his party was too soft on Sen. John McCain (R-Ariz.) on Monday night. “But I guarantee on the first night of the Republican convention, you’re going to hear talk about Barack Obama, commander in chief, tax cuts, et cetera, et cetera.”

In their 2006 book, titled Take It Back, Carville and Democratic strategist Paul Begala wrote that advisers to Sen. John Kerry (D-Mass.) were furious with former President Carter’s speech at the 2004 convention, which attacked President Bush’s track record.

Carter appeared at, but did not deliver a speech to, the convention on Monday. In their tome, Carville and Begala criticized the Kerry campaign for its concerns about Carter, noting the ex-president didn’t even mention Bush’s name and “didn’t ridicule him in the way the Republicans did Kerry.”

Obama spokesman Bill Burton indicated that changing speeches is nothing out of the ordinary.

“Just like all conventions, the campaign of the nominee is working with all of the speakers on the message of the convention,” Burton wrote in an e-mail.

Several speeches have had a rags-to-riches theme. In his address, Rep. Mike Honda (D-Calif.) said, “One of my proudest moments was when I received keys to my first classroom. It was high-quality public education that allowed this son of strawberry sharecroppers, raised in the Japanese-American internment camps of World War II, to grow up to become a Peace Corps volunteer, a vice chair of the DNC, and chair of the Congressional Asian Pacific American Caucus.”

In his address, Austin Esposito, the son of Sen. Claire McCaskill (D-Mo.), said, “My name is Austin. These are my sisters, Maddie and Lily. … How did we get here? Well, it started with few strong Americans. My great-grandmother Mildred was a single mom, which was tough. Thankfully, she was strong and independent and wasn’t afraid to state her opinions, even when women weren’t supposed to be heard from.”

Democratic strategist Peter Fenn — also a contributor to The Hill’s Pundits Blog — believes the best conventions are those with the most tightly controlled messages. “The important thing to come out of the convention is Barack Obama’s message,” he said. “They should be controlling the message.”

Burton, the Obama spokesman, said, “This year, we’re focused on making sure that the American people see how we’re showcasing Democrats, independents and, yes, even some Republicans. People who watch will get a crystal-clear sense of who Barack Obama is and the fundamental choice between Barack Obama, who wants to fundamentally change business as usual in Washington, and … John McCain, who offers just more of the same.”