VIEWER GUIDE: Can Barack Obama top his wife in Philly?

PHILADELPHIA (AP) - Can Barack Obama top his wife?

The president takes to the mic at the Democratic convention on Wednesday, two days after Michelle Obama wowed delegates with her forceful defense of Hillary Clinton.

Running mate Tim Kaine and Vice President Joe Biden are in the lineup, too.

Some things to watch for during Wednesday's session at the Philadelphia convention:

SUNNY SIDE UP

And now, a word from our president. President Barack Obama speaks at the convention on behalf of his onetime rival and former secretary of state. But he'll also be defending his own record. Republicans last week painted a dark portrait of an America under siege, beset by criminals and terrorists. Obama will offer a sunnier vision of the nation and of his presidency in one of his last big opportunities to frame his legacy before a mass audience. Expect Obama to rebut Trump's depiction of the nation, unfurling a list of upbeat statistics.

RAISING KAINE

Kaine's speech will be his introduction to a large swath of America. A CNN/ORC poll conducted over the weekend found that when Hillary Clinton's choice for vice president was announced, 27 percent of Americans said they had a favorable opinion of the Virginia senator and 19 percent an unfavorable one. More than half said they had no opinion or hadn't heard of him. But supporters of Bernie Sanders already are complaining loudly about Kaine's centrist views, including his past praise for the Trans Pacific Partnership trade deal. They'll be closely watching to see what, if anything, he says about the deal, which he came out against the day after joining the Clinton ticket. Some Sanders delegates have been discussing ways to register their unhappiness, including talk of perhaps turning their backs during his speech.

WOULDA, COULDA

This is not the convention moment that Joe Biden once longed for. The vice president thought long and hard about running for president himself before opting out. Asked about that decision in January, he confessed: "I regret it every day." But he added that it was the right call for him and his family. Biden's a loyal Democratic soldier and a popular figure within the party. Expect him to make a strong case for Clinton, and mix in some humorous self-deprecation along the way.

WOULDA, COULDA, PART II

Michael Bloomberg, who was elected mayor of New York City as a Republican, will stand at the Democrats' mic to speak on behalf of Clinton. He, too, considered a run for president. The billionaire media mogul opted against running as a third-party candidate for fear it might siphon away votes from Clinton and help elect Donald Trump. Bloomberg has been sharply critical of Trump, especially his fellow New Yorker's inflammatory rhetoric on immigration. Bloomberg was a Democrat before switching to Republican ahead of his successful 2001 run for mayor. Bloomberg later became an independent and a leading advocate for gun control. ___

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AP Polling Director Emily Swanson in Washington contributed to this report.

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Follow Nancy Benac on Twitter at http://twitter.com/nbenac