By Sunday, Bill Clinton sounded awful, as if he had been gargling with Liquid-Plumr. You could hear his voice dying steadily over the last 72 hours of campaigning: hoarse Friday in Florida, cracking Saturday across Virginia and dissolving fully to a slight husk here Sunday, after two stops in New Hampshire and before another in Minnesota.
“As you can see, I have given my voice in the service of my president,” Mr. Clinton said, wheezing while introducing President Obama at a late-night set at a Bristow, Va., amphitheater on Saturday. He kept coughing, patting his chest and mouthing words that carried only muffled strains in chilly air. Black tea with honey and a steady diet of cough drops between events helped little.
It was as if the 42nd president could go fully silent at any second, except that he never did — speaking for 25 minutes Saturday night and more than 40 at his nine solo shows over the weekend to cap off a campaign star turn that could not differ more from what many considered his more dutiful efforts for Mr. Obama four years ago.
After talking (and pointing and gesticulating) for three-quarters of an hour before a crowd of 4,000 at an amusement park here Sunday night, Mr. Clinton spent an additional 10 minutes high-fiving his way along a rope line with a big grin.
If there has been one enduring lesson from his career, it is that the Big Dog is resilient. He can be disgraced, impeached, defeated — but he comes back. The full spectacle of this has been on riveting, if raspy, display in the closing days of the presidential campaign.
Mr. Clinton, 66, has jumped into a hopscotch of battleground states in what — depending on his wife’s future plans — may or may not be his last campaign tour as a Super Surrogate. He is scheduled to appear, if not be heard, at four stops across Pennsylvania on Monday.
He also includes a fair amount in his speeches about Bill Clinton: his enthusiasm (higher than four years ago), his legacy (“I am the only living former president that ever gave you a budget surplus”) and, yes, his wife, the mention of whom brings big applause and the occasional “We love you, Hillary!” cry from the crowd.
Whoever wins Tuesday, the 2012 campaign has solidified (or restored) Mr. Clinton’s status as the hardest-working man in a game he loves and plays like no one else. “The master, Bill Clinton,” Mr. Obama called him on Saturday, hailing his predecessor as “a great president and a great friend.”
Unsaid, at least here, is that Mr. Clinton has also been a salvation to Mr. Obama. He gave what was widely considered the best speech at the Democratic National Convention in Charlotte, N.C., rocking a strong endorsement of the president while arguably conveying the re-election rationale better than Mr. Obama or his campaign has.
“He has been our economic validator,” Jim Messina, Mr. Obama’s campaign manager, said of Mr. Clinton.
Likewise, Mr. Clinton’s presidency exemplifies what Mr. Obama is trying to make a case for. In the early 1990s, President Clinton also inherited a lagging economy, and then he led economic prosperity in his second term. Mr. Obama, who wrapped his former rival in a full-on hug onstage in Charlotte (their recent joint appearances have featured more cursory bro-hugs), said he should name Mr. Clinton to a new position known as Secretary for Explaining Stuff.
Out of public view, the former president has been equally tireless. In a 20-minute car ride Saturday after a rally in Chesapeake, Va., to the Norfolk airport, Mr. Clinton recorded 40 “robo-calls” for Democratic Congressional candidates across the country. In addition to headlining 37 rallies for Mr. Obama over the last seven weeks of the campaign (including events scheduled through Monday), Mr. Clinton is serving as a back-channel strategist for the re-election enterprise.
On the morning after the third debate between Mr. Obama and Mitt Romney on Oct. 22 in Boca Raton, Fla., Mr. Clinton met Mr. Messina for an impromptu breakfast meeting in a suite at a Hyatt Regency hotel in Chicago. Red-eyed after arriving from Boca Raton at 3:30 a.m. and subsisting on Coke Zero, Mr. Messina received, he said, a simple directive from former president, who was in Chicago to give a speech: I am yours in the final weeks. Mr. Clinton said he would undertake a heavy regimen in battleground states.
Previously, Mr. Clinton had served as an active behind-the-scenes strategist, speaking regularly to the president, Mr. Messina and David Axelrod, the senior strategist. He made suggestions on what themes the campaign should emphasize and where. He advocated, according to top officials, for Mr. Obama to run advertisements in Florida that portrayed Mr. Romney as a threat to Medicare and Medicaid — something the campaign ultimately did. As he stumped across the state Friday, Mr. Clinton also drove home that portrayal.
During the Republican primary battle, Mr. Clinton also counseled Mr. Messina and Mr. Axelrod to “have an early conversation” with Democratic base voters in battleground states, so as not to let any disappointment they felt over Mr. Obama’s record calcify into indifference.
But by far Mr. Clinton’s most striking contributions have come in his natural Big Stage habitat. When Hurricane Sandy forced Mr. Obama off the campaign trail early last week, Mr. Clinton called Mr. Messina and suggested that he take on some of the events that the president would miss. Mr. Clinton stumped alone in Orlando, Fla., and with Vice President Joseph R. Biden Jr. in Youngstown, Ohio.
He has hailed Mr. Obama’s post-storm cooperation with Republican leaders like Gov. Chris Christie of New Jersey and has ridiculed Mr. Romney as wishy-washy enough to “be the chief contortionist for Cirque du Soleil.”
But subtext will inevitably abound in the Clinton orbit. For starters, while his “friendship” with the president is clearly improved, it remains a source of intrigue, given the strains that were sown during Mr. Obama’s primary run against Hillary Rodham Clinton in 2008.
“This is not about relationships,” said Terry McAuliffe, Mr. Clinton’s close friend, the former Democratic National Committee chairman and a possible candidate for governor of Virginia, where he accompanied Mr. Clinton on Saturday. “This is bigger than that.” By “bigger,” Mr. McAuliffe meant that Mr. Clinton is chiefly concerned with the direction of the country, not his relationship with anyone.
It also calls to mind a maxim uttered often among Democrats, and not always with reverence: that it is “all about the Clintons.” And it is not difficult to view Mr. Clinton’s investment in Mr. Obama’s re-election without an eye to whether Mrs. Clinton runs in 2016, something that she has denied interest in but that many Democrats have urged.
It is also impossible to miss what is Mr. Clinton’s most reliable applause line on the stump and something he manages to belt out in full voice.
“By the way,” he says in praising Mr. Obama’s foreign policy record, “he’s got a heck of a secretary of state, too.”
And the crowd always goes wild.