Aside from painting a clear picture of what he stands for, to convince voters to embrace his vision of how best to assure America's future, the Massachusetts senator faces two more immediate challenges: raising cash and choosing a running mate.
The Kerry campaign is a whopping $100 million behind President Bush in ready cash as he embarks on the next phase of his White House campaign, and dependent on outside groups he can't legally control to help close the gap.
At the same time, Kerry's aides say he brought in a record $1.2 million over the Internet in less than 24 hours after locking up the Democratic presidential nomination with a near-sweep of the Super Tuesday primaries and caucuses.
As for the running mate problem, Kerry Wednesday named Jim Johnson, a prominent Washington Democrat and former aide to Vice President Walter Mondale. Johnson is vice president of a merchant banking firm.
Kerry says he wants to keep the process private and won't "throw names around." He speaks from experience, having made Al Gore's short list in 2000 only to be passed over for Connecticut Sen. Joe Lieberman.
Kerry has said he wants someone he gets along with who also would be capable of assuming the presidency. The Massachusetts senator will also be looking for someone with strengths that negate his weaknesses.
The Kerry campaign has been vague about the timetable for a decision; vetting candidates often takes weeks. The benefit of a quick decision is a partner to help spread the message in competitive states, as well as to help raise money. The disadvantage is eliminating, early on, a guessing game that might keep the public captivated.
And, at least in some places, they are.
Campaigning Wednesday in Florida - site of the contested recount in 2000 and a battleground state this year - Kerry had two potential vice presidential candidates by his side: Senators Bob Graham and Bill Nelson.
Getting out of his vehicle for a town hall meeting in Orlando, Kerry was greeted by a throng of cheering supporters who clearly had the No. 2 spot on their minds.
"Pick Bob Graham!" yelled a man behind the rope line, referring to the state's senior senator who abandoned his own presidential bid last year. Graham is also retiring from the Senate when his term expires at the end of the year.
"Edwards!" responded another in the crowd.
Once inside, Graham gave a lengthy introduction full of praise for Kerry and condemnation for Bush.
Here's a rundown on some of the names being mentioned as possible vice presidential candidates:
HILLARY RODHAM CLINTON
Her memoirs have sold millions and national polls show the New York senator and former first lady remains one of the most popular Democratic figures. But Clinton also has high negative ratings, in part because of the aggressive role she played promoting former President Clinton's far-reaching health care agenda and cutting down his critics. Kerry shouldn't need help in winning Democratic-leaning New York.
Retired four-star general and former NATO commander makes him a credible wartime candidate, the same qualities already provided by Kerry - a decorated Vietnam veteran with experience in international affairs. But Clark is not a smooth campaigner and he stumbled several times while trying to explain his views on Iraq and abortion. Raised in Arkansas, he is a Southerner who could be popular with moderates, conservatives and those who value a Washington outsider.
The North Carolina senator and former trial lawyer raised his prospects as a running mate with a strong performance as runner-up to Kerry. His Southern roots and populist message provide balance to Kerry's Northeastern background and patrician upbringing, and exit polls showed he appealed strongly to Republicans and independents. But Kerry may want someone outside the Senate to gain maximum national appeal and there are questions about how well the two get along.
One of California's two female senators and a former mayor of San Francisco, Feinstein entered the Senate in 1992 to finish the two years remaining of Gov. Pete Wilson's term. Despite a new Republican governor in Arnold Schwarzenegger, the state will likely again swing heavily Democratic, making a California politician on the ticket little extra comfort for Kerry.
The longtime Missouri congressman would bring a lengthy political resume and regional balance to Kerry's Northeastern background. Gephardt's working class roots and devotion to organized labor play well in key states such as Ohio and Michigan, but Kerry may be looking for a running mate who isn't a creature of the Capitol; Gephardt has served in the House since 1977. Gephardt's two failed presidential bids also raise questions about how much he could broaden the appeal of a Democratic ticket.
Twice elected governor, the three-term Florida senator never lost a statewide contest in more than 35 years. Graham, who has announced he's retiring from the Senate, could help Kerry win one of the campaign's biggest prizes. Kerry has said Graham would be on anyone's list of potential running mates, but the senator, with his exhaustive notebooks, may not be a good fit.
As a Southerner and a woman, the second-term senator from Louisiana appeals to two obvious constituencies for Democrats. Landrieu showed some mettle in 2002 by hanging on to win a close re-election campaign in an increasingly conservative state against a Republican who was heavily touted by President Bush. A moderate on some issues, Landrieu could provide regional balance to Kerry's image as a Northeastern liberal.
Like Landrieu, the first-term Arkansas senator could help Kerry win votes from women and Southerners. She won a seat in the U.S. House in 1992 but left after four years to raise her twin sons. She returned to Congress in 1998 as a senator, where she emerged as a voice for farmers and rural families, but has little name recognition.
The first-term governor of Arizona could attract female voters and provide geographic balance as a Westerner, particularly from a Republican-leaning state. As a former attorney general and federal prosecutor, she also provides credentials as a crime-fighter. But Napolitano, 46, has maintained a low profile and hails from a state with few electoral votes.
A centrist senator from Florida serving his first term, Nelson might help deflect charges that Kerry is too liberal, but he is unknown outside of the state. Nelson - in politics since 1972 and the winner of 11 elections for three offices - could help secure Florida's electoral votes.
The chairman and CEO of mortgage lender Fannie Mae, Raines served two years in the Clinton administration as Director of the Office of Management and Budget. Raines, a Rhodes Scholar and former economic adviser in the Carter administration, was mentioned as a possible running mate to Al Gore in 2000. Having Raines, who is black, on the ticket could help bring in minority votes for Kerry, but Raines is relatively unknown outside Washington.
The first-term Pennsylvania governor and former Philadelphia mayor hails from a battleground state that Al Gore won by 5 percentage points in 2000. A former chairman of the Democratic Party, Rendell is credited with steering Philadelphia from the brink of bankruptcy in the 1990s. He now works with a GOP-dominated legislature and takes positions appealing to social liberals and business advocates. He would be only the second Jewish candidate on a Democratic ticket after Joe Lieberman in 2000.
The first-term governor of New Mexico would be the first Hispanic on a Democratic ticket, appealing to the nation's largest minority group and voters in the Southwest. Richardson served as Energy secretary in the Clinton White House, but his tenure was tainted by the botched prosecution of scientist Wen Ho Lee, who was charged with mishandling classified information and imprisoned for nine months. Lee pleaded guilty to one felony count of mishandling information and is now suing Richardson for defamation of character for allegedly leaking Lee's name to the media.
A former Treasury secretary under President Clinton, Rubin was viewed by many business leaders as the linchpin behind economic policies that fostered the nation's economic boom. He spent most of his life as a Wall Street trader at Goldman Sachs before joining the Clinton team. He's now a top executive at financial giant Citigroup.
The second-term Iowa governor has attained prominence as chairman of the Democratic Governors Association and was credited with helping Al Gore narrowly win the state in 2000. He did not formally back any of the Democratic candidates during the Iowa caucuses, but his wife Christie endorsed Kerry. Vilsack has dismissed questions about his interest in the vice presidency, but last month he delivered a scathing speech denouncing President Bush's economic policies.
The first-term Virginia governor may be a Southern transplant (he grew up in Connecticut) but his dogged determination traveling throughout the rural and mountainous areas of Virginia helped him win back former Democratic strongholds that had turned Republican. But Virginia is a Republican-leaning state and Warner's personal appeal may not translate into votes for Kerry in the South.