RALEIGH, N.C. — 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.