Senate Republicans were struggling to salvage a more than $1 trillion economic rescue package to respond to the coronavirus crisis when they got the message on Sunday afternoon: One of their own had been walking around the Capitol with Covid-19 for days as they debated how best to confront the rapidly spreading pandemic.
Senator Rand Paul had tested positive for the coronavirus, Senator Mitch McConnell, the majority leader, told fellow Republicans over lunch. It was the news that lawmakers had been dreading for weeks as they went about their travel- and handshake-heavy routines while the disease circulated around the country.
The news set off a frantic race to retrace the steps of Mr. Paul, who had continued to show up in the Senate — even using the private senators’ gym, where he swam laps in the pool on Sunday morning — until he received the results of his coronavirus test sometime after his workout.
It injected a potentially dangerous new element into the intense negotiation over a stabilization package to bolster the country’s health system and social safety net and to prop up an economy teetering on the brink of collapse.