ST. LOUIS • Jake Zimmerman didn't get the memo.

Huddled with young Democrats in a tiny conference room at the Union Station Marriott far from the big hall where Vice President Joe Biden would soon take the stage, Zimmerman, a Democratic state representative from Olivette, did what Biden wouldn't.

He mentioned Robin Carnahan's name.

Missouri's secretary of state, Carnahan is running for U.S. Senate in one of the most high-profile races in the nation. She faces an uphill battle against seven-term Congressman Roy Blunt, a well-funded Republican from Springfield who has a clear lead in most polls.

Zimmerman's message to about 15 members of the Democratic National Committee's Youth Council was a simple one.

"If young voters don't show up in this cycle, we lose," Zimmerman said.

A gregarious redhead, Zimmerman exuded energy about the Democratic Party and its Senate candidate.

"In any ordinary election cycle, our candidate ought to wipe the floor with (Blunt)," he said.

But this is no ordinary election cycle.

That point couldn't have been more clear not long after Zimmerman's speech, when the big names took the main stage elsewhere in the sprawling complex.

Kathleen Sebelius, the secretary of health and human services — and the former governor of Kansas — offered kind words about Missouri Sen. Claire McCaskill. Sebelius went so far as to compare her to the state's favorite son, former President Harry Truman. She even mentioned Gov. Jay Nixon.

Similarly, DNC Chairman Tim Kaine — a University of Missouri graduate — mentioned Nixon and McCaskill to the crowd of hundreds of Democratic delegates from all over the country.

But before Biden took the stage, neither of them mentioned the one Democrat — Carnahan — who is so integral to the party's chances of holding on to the U.S. Senate in November.

Neither did Biden. The vice president was fired up. He all but guaranteed that Democrats would be the big winners on Nov. 3.

"Were it not illegal, I'd make book on it," Biden said.

Biden praised Senate leader Harry Reid and House Speaker Nancy Pelosi. He even brought up Republican Senate candidates Rand Paul of Kentucky and Sharron Angle of Nevada, the poster children for what Biden called the Republican Tea Party.

But no Carnahan. Not once.

Such consistency in message — or lack thereof — is no accident.

Carnahan is stinging from Blunt's first big ad, the one showing President Barack Obama next to her at an event in Kansas City, mentioning how much he needs her vote to help accomplish his agenda.

And then Thursday happened. On the day Democrats arrived in St. Louis, Carnahan reversed course on the very Bush tax cuts that were lampooned in several speeches at Union Station. Carnahan now says she supports extending those cuts, even those that go to the "millionaires and billionaires" derided by Sebelius in her speech.

Therein lies the Missouri Democrat's dilemma.

Biden was at his rousing, fist-pumping best Friday morning, and Democrats cheered what they called the tremendous accomplishments of Obama: passing health care reform and financial reform and pulling combat troops out of Iraq. They were excited.

That agenda will push Democrats to victory in November, Biden said.

But Carnahan isn't really running on that agenda.

Carnahan backed the health care bill once it passed, but she is still quick to point to its faults. She backs elements of the cap-and-trade bill pushed by Obama but offers caveats to give her wiggle room. She rails on Blunt for his support of the Bush bailout but then suggests it might have been necessary.

Carnahan will ask DNC leader Donna Brazile to help her raise money at private parties while Brazile is in St. Louis, but she won't appear on the public stage with national Democratic leaders.

From a crass political standpoint, it's easy to understand why Carnahan wouldn't want her name mentioned on the DNC stage. The Obama ad run by Blunt was effective. And her flip on Bush tax cuts wouldn't go well in a room of folks quick to blame the former president for the nation's economic woes.

But if Zimmerman is right, and young voters are going to have to get excited for Carnahan to have a chance in her race against Blunt, then the coordinated effort to keep her name out of the DNC conversation raises a key question: How are new voters going to get excited about her if Democratic leaders won't say her name?