DENVER - When Democratic strategist Paul Begala wrote a $2,300 campaign check to Barack Obama recently, he scribbled in bold letters at the bottom: "FOR NEGATIVE CAMPAIGNING ONLY."
Obama burst into laughter when he saw the donation, Begala was told. But he and some other strategists won't be amused if Obama ignores their advice.
Increasingly nervous about polls that show a dead-even presidential race - and no bounce at all from putting Joe Biden on the ticket - these Democrats say it's time for Obama to escalate his attacks on John McCain or risk blowing an election that should be theirs for the taking.
"We Democrats always pull our punches," said Joe Trippi, a Maryland-based campaign consultant. When John Kerry muted his attacks on President Bush at the last convention, it was, Trippi said, "a big mistake."
Voters universally deplore negative campaigning, but strategists see a redeeming virtue: It works. They wonder whether Obama has the backbone to do what they think it will take to hold off McCain.
The Democrat's lead in the polls began disappearing not long after McCain aired a wave of TV ads that mocked Obama as a celebrity. The Republican convention, which opens Monday, is expected to be an Obama-bashing fest from start to finish.
Some Democrats complain that their party isn't doing the same. Attacks on McCain were not a prominent feature on the opening night of the convention, and last night's keynote speaker, Mark Warner, couldn't afford to alienate Republicans because he's running for the Senate in closely divided Virginia.
Obama's convention task is more complicated than McCain's, though. As a newcomer, he needs to introduce himself to voters and make them comfortable with the idea of him as commander-in-chief.
His advisers are assuring nervous Democrats that they'll turn up the heat on McCain as the convention shifts into its final two days. This week, the Obama campaign began airing a new attack ad that portrays McCain as clueless on the economy and claims the Republican "really can't explain the price of gas or what has happened to the middle class."
Those in the get-tough camp say the anti-McCain effort won't truly be effective unless Obama himself goes negative as part of a relentless, sharply focused attack.
"The biggest problem we're facing right now is defining McCain," said Peter Hart, a veteran Democratic poll-taker. "My biggest question is: Who is going to take on McCain?"
Obama aides have been quick to respond whenever he's attacked, and Obama himself has begun going after McCain in a more personal way. He seized on McCain's gaffe about the number of houses he owns to portray the Republican as out of touch with the economic struggles of ordinary Americans.
But he may be a reluctant warrior in the sort of all-out negative campaign the hardliners would like to see. In Obama's political history, he's never faced a tough general election foe.
From the start of his presidential run, Obama cast his candidacy as a vehicle for ending Washington gridlock and its "cheap political" point-scoring. That promise helped gain him his party's nomination, but it may also make it harder for him to take the offensive.
Republicans have pounced every time he criticizes McCain. They've accused Obama of abandoning his high-minded ideals, arguing the attacks prove that he is just another politician.
One of his closest friends in Washington, fellow Senate freshman Claire McCaskill of Missouri, says Obama can't be a cutthroat candidate. The reason, she said, has more to do with his personality than campaign strategy.
"Barack is never going to be a red-meat, attack-dog politician," she said in an interview on the convention floor. "I think he's got to be true to himself."
That sort of talk concerns advocates of rough-and-tumble tactics like Begala, who, along with his partner, James Carville, helped Bill Clinton become the only Democrat to win the White House in the last 30 years.
"The thing that matters most is what the candidate says," said Begala, who supported Hillary Clinton in the primaries. If Obama doesn't shoulder that responsibility, "then he will lose."
Defining McCain in negative terms is no simple task. His reputation for independent thinking and his sacrifice as a Vietnam-era POW are widely known, and seemingly immune to negative publicity about his ties to lobbyists or questions about his temperament.
But Democrats argue that he's done little to define an agenda for a McCain presidency and say that his positions on issues are wide open for attack.
"There's a disparity between the reality of John McCain and the way he's perceived," said Democratic Rep. Barney Frank of Massachusetts. He noted that McCain's role as a leading supporter of Texas conservative Phil Gramm's presidential campaign in 1996 is sharply at odds with McCain's public image.
"People think McCain is a moderate, a progressive," said Pennsylvania Gov. Ed Rendell, a former Democratic national chairman, in an interview.
Rendell said that between 20 percent and 30 percent of the voters in the southeastern part of his state, a key swing area, mistakenly believe that McCain supports abortion rights. McCain made conflicting statements in 1999, during his first run for president, about whether he favored repealing Roe v. Wade, the Supreme Court decision outlawing abortion, but his voting record and his current campaign statements are staunchly anti-abortion.
The Democrats' vice-presidential nominee, Biden, is likely to take the lead in going after McCain for the campaign. He is expected to preview his attack lines during his acceptance speech tonight.
"I think Joe Biden will go toe-to-toe with McCain. They picked him for that," said Trippi.
Trippi, a former adviser to the presidential campaigns of Howard Dean in 2004 and John Edwards this year, said Obama aides were right to focus more on their man's life story than on McCain and Bush during the early part of the Denver convention.
"People still need to know more about Obama," he said. "It would be a mistake to come in here with all guns blazing."