What’s more important for Sen. Barack Obama at the convention — to define himself or to define Sen. John McCain?

Obama has much to do at his convention. After a month of attacks from McCain’s campaign and time off the trail for a Hawaii vacation, Obama needs the convention to reenergize his own campaign heading into the final two months of the general election. Picking Sen. Joe Biden as his running mate began that process, but he has plenty more to do this week.

Republicans see Obama’s principal goal as defining himself, rather than defining McCain. “This election is all about whether Obama is, in the McCain campaign’s phrase, ‘ready to lead,’ ” Republican strategist Whit Ayres noted. “If a majority think the answer is yes, he wins. If a majority think the answer is no, McCain wins.”

Democrats have two views. Many agree with Republicans about the need for Obama to use the week to fill out his personal story. “Obama is in a similar position to Bill Clinton in ‘92,” Democratic strategist Tad Devine said in a message. “People need to get a handle on him. In the end, this election is about him. He needs to let people know as much about his values and priorities as he can in four days.”

Other Democrats believe a far more urgent priority for Obama is to frame the choice for voters as clearly and as starkly as he can. “The images of both men are by now indelibly imprinted on voters’ minds,” wrote Rick Sloan of the International Association of Machinists. He added: “Rather than wasting time defining himself or his opponent, Senator Obama should define his pathway for changing the direction of this country.”

But Obama and his surrogates dare not make the entire convention about him. Four years ago, most of the creative efforts at the party convention focused on Sen. John Kerry’s biography and Vietnam War record, and it was assumed that people didn’t need to talk about President Bush. That approach is now seen as a big miscalculation. “Obama needs to define himself, but others must define McCain,” wrote Howard Wolfson, communications director for Hillary Rodham Clinton’s presidential campaign. “We cannot repeat the mistake of the ‘04 convention.”

Have Democrats truly gotten over the long Obama-Clinton battle?

The Obama-Clinton drama is the second most important story line of the Democratic convention. Obama needs a party that is either fully united or clearly heading rapidly in that direction by the time Democrats break camp on Thursday night.

Sen. Hillary Rodham Clinton has been virtually pitch-perfect in her public appearances in behalf of Obama since the primaries ended, but this has not not always been the case for some supporters and her husband, former President Bill Clinton. Her speech today and her husband’s speech Wednesday will be dissected by the media, by the Republican and by loyalists in both camps for evidence of whether the wounds from the primaries have healed.

Republicans are gleeful over the possibility of continued divisions. They are ready to seize on any signs of division within the Democratic family to sow further discord. “As long as Hillary’s forces continue to be sore losers and Obama’s people are arrogant sore winners, they will never fully heal,” GOP strategist Todd Harris said.

That may be wishful thinking. What is key for Democrats is not for the Clinton loyalists to forget their disappointments, but to rally behind Obama and Biden in spite of them. The convention should move them a significant step closer to that goal — and many Democrats are confident both Clintons will deliver.

“This will be one of the major positives from this convention,” Democratic strategist Bill Carrick noted.

“By election day,” predicted Democratic pollster Mark Mellman, “Obama will get nearly 90 percent of the Democratic vote.”

Will Obama’s Invesco Field acceptance speech reinforce the Republicans’ “celebrity” message or transcend the attacks?

Hoopla is unavoidable — even necessary — for a successful acceptance speech. Obama and his forces have doubled down on Thursday’s grand finale to the convention by moving it out of the relatively cramped Pepsi Center to the home field of the NFL’s Denver Broncos.

Obama never has trouble drawing a crowd, whether it was 20,000 in Austin, Texas, at the beginning of the campaign or the 200,000 in Berlin last month that triggered the McCain “celebrity” attacks.

But crowd size and enthusiasm are sideshows to what really counts Thursday. For Obama, that means it’s all about substance.

Obama’s team sees opening up the acceptance speech to tens of thousands of ordinary people as a symbol of the grass-roots energy and volunteer spirit that helped power Obama to the nomination. But some Republicans say he risks sending the wrong message. “Americans around the country might be turned off if it looks too much like self-proclaimed movement,” GOP strategist Ron Bonjean noted.

Democrats see few risks. They think that Obama will hit the right notes with his speech, and that the visuals will enhance rather than distract from a message aimed at framing the election. Even many Republicans think Obama may pull it off.

“As effective as the McCain campaign hits on Obama’s celebrity have been, the outdoor speech is still going to be a home run for him,” noted Dan Schnur, who worked for McCain in 2000 and is now at the University of Southern California. “But he’d better bracket it with some round-table events to bring himself back down to earth.”

Will the convention produce a big bounce in the polls for Obama?

McCain’s forces upped the ante when they put out a memo predicting that Obama will get a 15-point bounce out of the convention. Few believe that’s likely, probably not even the people who put that into circulation.

There were predictions that Obama would get a healthy bounce once he wrapped up the nomination in June. That didn’t happen. There were similar predictions when he set out on his tour of the Middle East and Europe in July. Once again, the predictions proved faulty.

Strategists from both parties were all over the lot when asked to project Obama’s likely bounce. Where there’s widespread agreement is that the campaigns are in uncharted waters because the Democratic and Republican conventions are back to back this year. Whatever bounce Obama gets could be blunted quickly by the announcement of McCain’s running mate and the opening of the GOP convention.

Measurements of Obama’s bounce will be further affected by the fact that the pollsters will be conducting their post-convention surveys over the Labor Day weekend. The best advice is to pay only limited attention to the numbers this weekend and the weekend after the Republican convention — tell that to the media! — and see where the race stands in mid-September.

Will Obama’s choice of Joseph Biden as his running mate make any difference?

Judging by the immediate reaction, Biden’s addition will be a significant plus for Obama at the convention.

Democrats who remember Sen. John Edwards’s reluctance to go after Bush in 2004 were cheered by Biden’s attacks on McCain when he was introduced as the vice presidential candidate on Saturday. Organized labor couldn’t be happier with the choice, seeing in Biden a kindred spirit whose Irish Catholic, working-class roots will help overcome the lack of enthusiasm for Obama with that crucial demographic.

But one of the most telling compliments came from the other side of the aisle. “The choice strikes me as the choice of a highly confident campaign,” Republican Tom Rath noted. “I think this means that the campaign thinks they understand the playing field and is not surprised by what they see. In the end the wisest choice was the safest choice.”

Beyond the convention, it’s not clear the Biden choice will make any real difference. Dan Quayle proved in 1988 that even a disastrous introduction and a woeful debate moment can’t sink a ticket: George H.W. Bush won that election over Michael Dukakis with relative ease. If Biden generates energy in Denver and delivers in the vice presidential debate, that’s all Obama can ask for.

Which voters will Obama have uppermost in mind when he speaks on Thursday?

This isn’t a close call, judging from the responses of strategists in both parties. The number one target for Obama, they say, should be white, working-class voters who he struggled to attract against Clinton in the primaries.

Certainly there are a variety of constituencies Obama might have in mind: independent voters who could hold the key to victory this year; Latinos, whose support will be critical in deciding the outcome; young voters, whom Obama needs in big numbers in November; women, because they are the backbone of the Democratic coalition.

But given the obvious weakness he displayed in the primaries and because the economy now is the dominant issue in the minds of voters, there’s a sense among strategists outside Obama’s campaign that he needs to focus like a laser on the insecurities and anxieties of the working class and middle class.

“I’d be thinking about a 50-year-old man or woman who is not a college graduate, with kids who are struggling to get started on their own and with the first grandchild on the way,” noted Geoff Garin, a Democratic pollster who was co-chief strategist of Clinton’s campaign in the closing months.

Others offered subsets of that population. John Feehery, a Republican strategist, said Obama’s target should be Roman Catholics. A Clinton loyalist suggested “those 18 million Democratic primary voters who voted for someone else.” Democratic strategist Tad Devine said the real targets of Obama’s speech should be women, particularly those without college degrees.

What can McCain do to compete with the Colorado show?

There was a time when the opposition candidate took much of the week off during his rival’s convention. That’s not possible any more, but most strategists think whatever he tries will be drowned by the saturation coverage of the Democrats.

What McCain did was send his surrogates to Denver to insert some Republican reaction into the stories coming out of the Pepsi Center. McCain will campaign some and the media will try to pay at least modest attention to him.

The best thing he can do, say his GOP friends, is try to make a modest splash as the Democratic convention opens, then announce his vice presidential running mate on Friday to grab the spotlight heading into the Republican convention in St. Paul, Minn., Monday.

Will the Denver convention turn Colorado and other Mountain states blue in November?

Convention locations have little impact on a party’s political fortunes in specific states. George W. Bush had his convention in Philadelphia in 2000 but still lost Pennsylvania — and lost the suburbs of Philadelphia badly. His 2004 convention was set in New York and he lost statewide too, though the city offered a Sept. 11 backdrop to frame national security as the key issue in the campaign.

Democrats chose Denver to make a clear statement that they intend to compete hard in the Rocky Mountain states. Colorado, New Mexico, Nevada and Montana all are on Obama’s target list. But most strategists agree that what will count in November are the demographic and political forces that are changing this part of the West, not that the Democrats came to Denver for their convention.

Still, there could be an impact on Colorado. Obama’s campaign decided to open up the acceptance speech to a huge audience in part as an organizing tool. They are counting on those who get tickets for the Invesco Field event to return to their communities energized and committed to helping Obama turn out the vote.