Get ready: The election is 100 days away

(CNN)Now it's on to the real fight.

The balloons have dropped, and the Republican and Democratic conventions are in the rear view mirror.
Election Day is now 100 days away and Donald Trump and Hillary Clinton are fanning out across hotly contested battleground states that could decide the election.
    The candidates are coming out of conventions that painted vastly different visions of America. In Cleveland, Trump described a nation under siege from crime, terror attacks and economic dislocation. In Philadelphia, Clinton and surrogates including President Barack Obama rejected that vision, describing a country facing challenges but poised to overcome them.
    Clinton set off from her convention Friday on a bus tour through Pennsylvania and Ohio with her running mate Tim Kaine. Joined by their spouses, Bill Clinton and Anne Holton, Clinton and Kaine vowed their policies would help middle-class America as they cast Trump as a "You're Fired" president.
    Making a direct pitch to lower-income and middle-class Americans, Clinton pledged to focus on areas of the country "left out and left behind" and "places hollowed out by plant closures."
    "We've got work to do. I'm not satisfied with the status quo. I'm not telling you everything is peachy keen. I'm telling you we've made progress but we have work to do," Clinton said. "We've got to make this economy work for everyone -- not just those at the top."
    Kaine, who introduced Clinton, described the former secretary of state as someone who "knows how to battle and get things done for regular people."
    "Don't you want a president who knows how to battle and get things done for regular people?" Kaine said as he introduced Clinton. "So that's what we'll do over the next couple of days: We'll talk about creating jobs, we'll talk about raising wages, we'll talk about the leadership that America needs to play in the world."
    Trump was in Colorado Friday, a swing state that already looks to be slipping away from the GOP. He abandoned his modest dismissals of the "lock her up" chants his supporters have aimed at Hillary Clinton.
    "I've been saying let's just beat her on November 8," Trump said a day after Clinton ripped him during her convention speech. "But you know what, I'm starting to agree with you."
    He went on: "You know it's interesting. Every time I mention her, everyone screams 'lock her up, lock her up.' They keep screaming. And you know what I do? I've been nice. But after watching that performance last night -- such lies -- I don't have to be so nice anymore. I'm taking the gloves off."
    Trump said there would be "no more Mr. Nice Guy."
    He is also pushing back against Khizr Khan who delivered one of the most powerful speeches at the Democratic convention. Khan, whose son Army Capt. Humayun Khan died in Baghdad in 2004, repeatedly blasted Trump's immigration proposals -- specifically those aimed at barring Muslims -- and said the billionaire businessman has "sacrificed nothing and no one."
    "Who wrote that? Did Hillary's script writers write it?" Trump said in an interview with with ABC News' George Stephanopoulos that will air Sunday. "I think I've made a lot of sacrifices. I work very, very hard."

    Flawed rivals

    Given that both candidates labor under historically low approval ratings, each campaign hopes to make the election a referendum on a flawed rival.
    The Clinton campaign is portraying Trump as shockingly unready to be commander in chief, seizing on his stumbles on national security to effectively scare Americans about the prospect of him in the Oval Office.
    "A man you can bait with a tweet is not a man you can trust with nuclear weapons," Clinton said in her convention speech on Thursday.
    The Trump campaign, however, appears convinced that the election will not turn on their candidate's character but on Clinton's personal liabilities. Riding the outsider wave that helped him win the GOP primary, Trump will present the former secretary of state as a jaded symbol of the elite status quo in a country he says thirsts for the fix-it skills of a strongman leader.
    "Excluded from Hillary Clinton's America are the suffering people living in our inner cities, or the victims of open borders and drug cartels, or the people who've lost their jobs because of the Clintons' trade deals, or any hardworking person who doesn't have enough money to get a seat at Hillary Clinton's table," said Stephen Miller, a senior Trump adviser in a statement.
    At the conventions, each campaign took a clear populist turn. It's a sign both sides know Trump's best hope of winning the election relies on turning blue collar Democrats into Republicans in the Midwest.
    The latest CNN/ORC poll published after the big GOP party but before Clinton's nomination in Philadelphia showed the billionaire led the former secretary of state 48% to 45% -- a 6-point gain from a pre-convention season poll.
    Polling shows a close race in the dozen or so swing states that will decide the election. But the map still favors the Democrats. Clinton can count on roughly 236 electoral votes so far, according to a CNN estimate, while Trump has 191 apparently locked up.
    It may be several weeks until the post convention turmoil settles — and media coverage of the Olympics could also provide a rare breather in this intense campaign.
    But the electoral mathematics are coming into focus.
    To win in November, Trump must improve upon the battleground performance of GOP nominee Mitt Romney in 2012. If he can peel away Pennsylvania, last won by the GOP in 1988, and take Ohio, and Florida and keep North Carolina, he will be en route to the White House. Alternatively, he could add Iowa and Michigan to Ohio, Florida and North Carolina and still get there.
    Clinton has more routes to the 270 electoral votes needed to win, given her ethnically diverse coalition. If, for example, she consolidates the states where she leads now, holds Pennsylvania and wins Florida, she will come out on top.
    And, if Clinton's team of surrogates including President Barack Obama, first lady Michelle Obama, Vice President Joe Biden and former President Bill Clinton, can energize the 2008 and 2012 Democratic presidential coalition of black, Latino, young and highly educated voters, she will be in strong shape.
    But no one should underestimate Trump. Given his capacity to rewrite political convention this cycle, it's likely that uncertainty over the result will linger right up to election night — whatever the polls say.
    As they set off down the stretch, each candidate has serious challenges.
    Trump, after becoming embroiled in a controversy over Russian espionage this week, is under pressure to pass the commander in chief test.
    His political ground game must quickly gear up to compete with Clinton's far more sophisticated operation, since a few thousand votes could make a difference in the most hotly contested states. And he must ensure that desertions from establishment Republican voters who despair at his brash, divisive style are compensated by bringing new voters into the fold.
    Clinton, meanwhile, will continue to face problems in an electorate where many voters simply do not like her. Doubts about whether she can surmount her trust issues are likely to track her all the way to election day. And she needs Bernie Sanders to keep uniting the troops of his political revolution behind her.
    Then there are the unknowns that both candidates will confront in the next three months. October surprises such as a major national security crisis could upend the campaign.
    Tepid economic growth figures released of the second quarter on Friday showing only a 1.2% GDP expansion in the second quarter will meanwhile have alarmed Clinton headquarters. If fears of a slowdown begin to eat into Obama's approval rating, Clinton could be damaged as she is effectively running as an incumbent seeking a third White House term for her party.
    The campaign that reacts most nimbly to such outside challenges in a close race may end up celebrating 101 days from now.