Editor's Note: (Errol Louis is the host of "Inside City Hall," a nightly political show on NY1, a New York all-news channel. The opinions expressed in this commentary are solely those of the author.)
Philadelphia(CNN) It's only fitting that President Obama's blockbuster speech in support of Hillary Clinton was delivered 12 years to the day after he burst onto the national stage at the 2004 Democratic convention in Boston. To win the presidency this fall, Clinton must inherit, energize, expand and mobilize the Obama coalition, a unique potent alliance that represents a key part of the President's legacy -- and Clinton's best hope for victory in November.
Behind the soaring oratory was a plea to Obama's core supporters -- the black, Latino, college-educated, women and independent voters that put him in the White House -- to transfer their loyalty to Clinton.
"Tonight, I ask you to do for Hillary Clinton what you did for me," Obama told the crowd of 20,000 at the Wells Fargo Center. "I ask you to carry her the same way you carried me. Because you're who I was talking about 12 years ago, when I talked about hope -- it's been you who've fueled my dogged faith in our future, even when the odds are great; even when the road is long."
It's her surest way to win, given Obama's healthy approval rating, currently around 50%, and his enduring appeal to black women voters, a pillar of the Democratic Party that boasts a sky-high 74% participation rate, higher than any other racial or ethnic subgroup.
Clinton will need a similarly high turnout by black voters to win. The Cook Political Report analyzed Obama's re-election numbers in 2012 and concluded: "African-American voters accounted for Obama's entire margin of victory in seven states: Florida, Maryland, Michigan, Nevada, Ohio, Pennsylvania and Virginia. Without these states' 112 electoral votes, Obama would have lost decisively. African-Americans also accounted for almost all of Obama's margin in Wisconsin."
Two other parts of the Obama coalition, liberal Republicans and independent voters, got a targeted appeal from former New York City Mayor Mike Bloomberg, a billionaire and ex-Democrat who won the mayoralty running as a Republican and an independent (under New York election rules, candidates can run on more than one party line).
"I know what it's like to have neither party fully represent my views or values," Bloomberg said, acknowledging that his appeal was targeted not at the assembled Democrats of the convention, but to Republicans and independents watching on television.
"There are times when I disagree with Hillary. But whatever our disagreements may be, I've come here to say: We must put them aside for the good of our country," he said. "And we must unite around the candidate who can defeat a dangerous demagogue" -- that last line a jab at Donald Trump.
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A third part of the Obama coalition, Latino voters, are key supporters of Obamacare; according to one recent poll, 54% of them want the next president to continue the health care initiative. That is why Clinton, who wants to carry heavily Latino swing states like Florida, Nevada and Colorado, strongly defended Obamacare against Sen. Bernie Sanders.
With just over 100 days to go before Election Day, expect Clinton to cling to black, independent and Latino voters like a life preserver -- because, politically speaking, that is what they are.