Barack Obama says people are sure to love him once they get to know him.

For now, though, Democrats seem to love Hillary Rodham Clinton more, so Obama is trying to turn heads with select jabs at his chief rival.

Obama's criticisms of the two-term senator and former first lady have been regular but subtle reminders that for all his campaign money and promises of hope, he still trails her in most national and early state polls.

And when you're No. 2, the only option is to chip away at the front-runner.

Among his criticisms in recent weeks, Obama has:

— Rejected the notion that she's more prepared for the job. "The only person who would probably be prepared to be our president on Day One would be Bill Clinton — not Hillary Clinton," he said.

— Repeatedly reminded voters that she supported the Iraq war resolution, trying to cut off any credit she might get for trying to repeal the authorization now. "There are no do-overs on an issue as important as war," he said, and called her approach is "convoluted."

— Pushed back at Clinton's efforts to portray herself as a candidate for change. "Change can't just be a slogan," Obama said. "Change has to mean that we're not doing the same old thing that we've been doing."

The heart of Obama's campaign is convincing voters that Clinton is a Washington establishment candidate — the quasi-incumbent, as his campaign manager called her recently — while he will bring fresh views for voters tired of politics as usual. But he has to walk a fine line when it comes to criticizing his opponents so voters don't see him as just another politician on the attack.

"It's risky territory for someone presenting himself as a 'hope-monger' who will 'turn the page' on traditional politics," said Dan Newman, a Democratic strategist in California. "The slightest whiff of negativity from Obama runs the risk of causing voters to question his carefully built self-presentation of a new kind of candidate who floats above traditional sniping and snapping."

That's why the most direct attack on Clinton from his campaign so far has not come from the candidate himself, but in a memo that criticized her ties to India and called her the senator from Punjab. When the Clinton campaign obtained the memo and distributed it publicly, Obama said it went over the line.

The Clinton campaign has its own subtle way of criticizing Obama, quickly pointing out when he is critical of her to try to portray him as a hypocrite. Newman said Obama's comment that only Bill Clinton would be ready to lead from Day One "was relatively tepid criticism, but her camp smartly seized the opportunity and fronted the article on her Web site."

Obama says changing the political tone does not mean he won't draw distinctions in the race. He said he's trailing Clinton now because she is so well known and he is not, but he expressed confidence that will change.

"To know me is to love me," the candidate said with a wide smile during a news conference Tuesday.

An Associated Press-Ipsos poll out this week shows that while Clinton and Obama are in a tight race for self-identified "moderate Democrats," Clinton has a strong lead among those who describe themselves as "strong Democrats." The more partisan voters are more likely to vote in the primary, so Obama needs to win them over by sowing the seeds of doubt about their favorite.

None of the Democratic candidates has really taken the gloves off with the kind of open and sharp attacks that have been seen on the Republican side. Many, including Obama, are still introducing themselves to voters and don't want to break on the scene with a negative attack.

And he must be careful not to strike too hard, said Jamal Simmons, a veteran of four Democratic presidential campaigns.

"The tough part for Senator Obama or anyone is how to criticize Senator Clinton without getting crosswise with Democrats and their affection for the Clinton family," Simmons said.