Raleigh – Hillary Clinton unleashed top surrogates including campaigner-in-chief President Barack Obama to bolster her case on Thursday in the election's home stretch, as rival Donald Trump deployed wife Melania to soften his image in crucial battleground states.As a slew of polls showed the race tightening with just five days to go, the campaigns brought all hands on deck in a handful of states that will decide the rollercoaster election.Obama shuttled into Florida for fiery rallies aimed at turning out the Democratic base for Clinton in a must-win state for her rival Trump, who is under pressure to snatch battleground states and even poach one or two Democratic strongholds if he is to prevail.A CBS/New York Times nationwide survey showed Clinton's lead shrinking to three points, at 45% against Trump's 42%, a sign the bombastic mogul is winning over once-wary Republican voters.After months of vitriolic and turbulent campaigning, political tribalism appears to be returning to the fore in the deeply divided nation ahead of Election Day on November 8."This will be a close race and you cannot take it for granted," Obama warned supporters in Jacksonville, Florida, painting an apocalyptic vision of what Trump would mean for American democracy.'Incredibly dangerous'Clinton added to the portrayal, telling North Carolinians that "if Donald Trump were to win this election we would have a commander-in-chief who is completely out of his depth and whose ideas are incredibly dangerous"."Are we going to work together to build a stronger, fairer, better America?" Clinton asked. "Or are we going to fear the future and fear each other and hunker down and be paralysed by all of our prejudices?"North Carolina, with its changing demographics, is critical for both camps, and Clinton and Trump were holding duelling rallies in the state on Thursday.Their motorcades even passed one another on the tarmac at Raleigh-Durham's airport.But the Democrats' last stand will come in Philadelphia on the eve of the election for a joint rally binding America's two most powerful political dynasties.Clinton will be joined by her husband Bill Clinton, President Obama and 2016's most potent campaigner, First Lady Michelle Obama.For sure the state of Pennsylvania is a firewall for Clinton; a Trump win there would be a giant step toward him becoming the 45th president.But a rally in Philadelphia – the City of Brotherly Love – sends an unmistakable message: Trump is a threat to the republic.It was here that the United States Constitution came into being in 1787.'Coming home'Melania Trump, the Slovenian-born former model who could become America's first foreign-born first lady in two centuries, also chose Pennsylvania on Thursday for her first solo campaign appearance."He certainly knows how to shake things up, doesn't he?" she said of her husband's incendiary campaign.Trump's third wife insisted her husband, with whom she lives in opulence, was running to improve the lives of suffering workers, struggling parents and children.She also made a bold play for the votes of suburban mothers, who could make all the difference in the tightly-contested state where Clinton's lead has narrowed, by fretting that "children and teenagers can be fragile".Despite the Manhattan mogul's boasts about sexual assault and allegations of groping by several women, white women are evenly split between the candidates, the CBS poll showed.As the race goes down to the wire, profound Republican skepticism about Trump's controversial candidacy appears to be ebbing."I think Republicans are coming home," Congressman Jason Chaffetz told CNN.Similarly, Clinton's FBI troubles appear to have dissuaded few Democrats, with only 8% saying it would make them less likely to vote for the former secretary of state.But in new ads on Thursday, Trump hammered home the message that Clinton put America at risk by using a private email server while secretary of state, and that a renewed FBI probe into the scandal shows she is "unfit to serve" – language Clinton often uses to describe her rival.'Nervous' DemocratsWith the campaign now in its final stages, each candidate is making closing arguments to voters, with Trump sticking to the teleprompter and avoiding his most explosive rhetoric."Nice and cool. Right? Stay on point, Donald, stay on point," the 70-year-old billionaire said out loud during a rally in Florida.That prompted mockery from Clinton. "His campaign probably put that in the teleprompter," she sneered.While Trump has no room for error on the electoral map, Clinton has sought to expand into Republican territory, notably Arizona, where she attended a huge rally on Wednesday.Her running mate Tim Kaine visited the border state on Thursday, making a play for Hispanic voters by delivering his remarks entirely in Spanish.Trump has ridden the aftershocks of the Great Recession and waves of antipathy toward the political elite to the brink of presidential power.Financial markets lurched this week as the race has tightened – trying to "price-in" a Trump victory that they had long thought impossible.Could he cause an upset?"Democrats are quite right to be nervous about the outcome," said a team of political analysts at the University of Virginia.But, they added, there was no "compelling argument" that the race favours Trump, or is even a toss-up.